The Effect of Educational Intervention based on Pender’s Health Promotion Model on Calcium Consumption among Pregnant Women

doi:10.21203/rs.3.rs-2343454/v2

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The Effect of Educational Intervention based on Pender’s Health Promotion Model on Calcium Consumption among Pregnant Women

https://doi.org/10.21203/rs.3.rs-2343454/v2

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Background and objective: The consumption of calcium-rich foods among pregnant women has always been one of the challenging issues of the health care system. The present study aimed to evaluate the effect of educational intervention based on Pender’s HPM on the calcium intake of pregnant women.

Materials and method: The pregnant women at three to five months were recruited using convenient sampling method and randomly assigned either to the control (n=37) or intervention (n=36) groups referred to the health centers in Kermanshah, Iran in 2019, 2020. Interventions were implemented based on the structures of Pender’s HPM with three assessments at baseline, immediately after the intervention, and after a one-month follow-up. The food frequency questionnaire was completed before and after the intervention. Data were analyzed in SPSS software version 25.

Results: There is no significant difference between the intervention and control groups at baseline (P<0.05). According to the independent sample t-test, all constructs of the Pender’s HPM except for interpersonal influences were significantly improved in the intervention rather than control groups (P>0.05).

The repeated measure ANOVA demonstrated a significant difference in the effect of the intervention on the constructs of the knowledge (F=9.40; P-value=0.001), perceived benefits (F=17.24 ; P-value=0.001), perceived barriers (F=40.80 ; P-value=0.001), perceived self-efficacy (F=10.90; P-value=0.001), activity-related affect (F= 14.85; P-value=0.001), interpersonal influences (F=21.51 ; P-value=0.001), commitment to a plan of action (F=20.20 ; P-value=0.001), and immediate competing demands and preferences (F=9.4; P-value=0.001) between the intervention and control groups. However, a significant difference was not observed in the construct of situational influences (F=1.20; P-value=0.296). The ANOVA demonstrated that the calcium consumption significantly increased in the intervention group (P<0.001).

Conclusion: Educational intervention based on the HPMchanged the nutritional behavior of calcium-rich food consumption among pregnant women. The use of Pender's HPM is recommended to improve nutritional behaviors. A theory-based educational intervention in the health care system can fill the gap in the successful implementation of nutrition education programs.

Behavior

calcium

dairy products

education

health promotion

pregnant

Pregnancy as one of the most important periods with commonly medical complications in women’s life, is associated with the enhancement of nutritional needs. Further, pregnancy influences the lifestyle and nutrition behaviors of women and their families (1). The malnutrition or inappropriate nutrition during pregnancy leads to a range of maternal and fetal complications, such as intrauterine growth restriction (IUGR), small for gestational age (SGA), preterm delivery (2), premature rupture of membranes break, polyhydramnios, oligohydramnios, pre-eclampsia, spontaneous abortions, medically induced labor, fetal death, fetal distress, fetal growth restriction, and malformations(3).

The fetus meets all its needs from the mother during its growth and development and inadequate nutrients in the mother leads to the depletion of the body’s reserves and maternal weight loss (4, 5). The need for calcium in the diet increases during pregnancy and pregnant women, especially in the third trimester are at risk of calcium deficiency (6). Human pregnancy is associated with changes in calcium and bone metabolism, supporting the calcium transport between mother and fetus.

Milk and dairy products are determinant in providing protein and calcium needed during pregnancy and preventing some complications, such as osteoporosis and tooth decay (7). The findings of conducted studies indicated that consuming more dairy products, such as milk and vitamin D during pregnancy may reduce the risk of newborn respiratory distress syndrome (8). Calcium deficiencies during pregnancy can lead to retardation of fetal skeletal growth and low level of calcium in the mother’s milk (9). In the same vein, women with multiple births who did not receive enough calcium may suffer from osteoporosis (10). A large number of studies indicated the significant role of calcium in preventing pre-eclampsia (11). Low calcium intake is associated with hypertensive disorders in pregnancy (12). Accordingly, calcium plays significant role in insulin resistant syndrome (13–15)

World Health Organization (WHO) and Food and Agriculture Organization (FAO) recommended dietary calcium intake of 1200 mg/day for pregnant women (16). Some studies demonstrated that the calcium intake among Asian women is lower than the recommended values (17, 18) and the prevalence of calcium deficiency in different months of pregnancy varies from 19% − 33.5% among Iranian mothers (19–21). A wide number of foods contain calcium (22), such as milk and milk products (providing 34–60% of calcium intake amongst adults) (9, 23) and cereals and cereal products (providing 30% of calcium intake).

cereals and cereal products (providing

30% of intake

cereals and cereal products (providing

30% of intake)

cereals and cereal products (providing

30% of intake)

Additional sources of calcium include plant foods,

including soya beans, some animal products (

e.g.

eggs) and water.

Additional sources of calcium are plant foods, including soya beans, some animal products (e.g. eggs), some mineral waters (9), and calcium supplementation (24). Identifying the bioavailability of these calcium sources is essential that is in turn considerably different. Milk and milk products are recognized as the main source of high bioavailable calcium with an average calcium content of 1150 mg/L (25–28).

Therefore, advice and education about increased dairy product consumption seem to meet the extra needs of pregnant women. Recommendation for consuming calcium-rich foods includes a part of the routine health care of pregnant women in Iran (21). However, reaching sufficient amounts of calcium is still a challengeable issue among Iranian pregnant women (25).

Studies indicated that desirable nutritional behaviors can be promoted by improving self-efficacy, commitment to action, positive emotions related to behavior, the perceived benefits of performing the behavior, perceived sensitivity, perceived severity, and the reduction of perceived barriers among overweight women (29). Pender’s HPM, including many of the afore-mentioned variables, as one of the health promotion models (14, 30) can be effective for intervention among pregnant women. Based on the available evidence about the effectiveness of Pender’s HPM in nutritional behaviors, the model seems to be successfully used in improving calcium consumption behavior of pregnant women (31,32). Therefore, the present study aimed to assess the effect of educational intervention on improving calcium consumption of pregnant women based on Pender's HPM.

Study design and participants

This is a semi-experimental study that its accessible population consists of the pregnant women referred to the health centers in Kermanshah, Iran from November 2019 to January 2020. First, the samples were selected from three health centers with similar socioeconomic, social, and cultural status using convenient sampling method and based on the inclusion criteria. Then, they were randomly assigned either to the control (n = 37) or intervention (n = 36) groups.

The inclusion criteria were pregnant women with gestational age of three to five months who had reading and writing literacy. The exclusion criteria included mothers suffering from acute digestive disorders, such as absorption disorders and irritable bowel syndrome (IBS) diagnosed by the center doctor, and pregnancy poisoning, including eclampsia and pre-eclampsia.

From all eligible pregnant women, 73 individuals were recruited in the study considering the inclusion and exclusion criteria. (Fig. 1).

Before the intervention, the informed consent form was obtained from all the participants with the explanation of the objectives of the study. Further, they were assured that their names and information would remain confidential and they could leave the study whenever they want.

Measurements

Demographic characteristics questionnaire

This researcher-made questionnaire included the variables of age, level of education, occupation, family income level, place of residence, and type of insurance.

Nutritional Behavior Questionnaire Based On Pender’s Health Promotion Model

This questionnaire with 60 items was used based on the constructs of Pender’s PHM with a 5-point Likert scale (except for the construct of awareness and interpersonal influencers) best situation (always/completely agree = 5) and the worst situation (never/ completely disagree = 1). The questionnaire consisted of eight items of knowledge (the lowest score = 0 and the highest score = 8), five items of perceived benefits (5–25), four items of perceived barriers (4–20), five items of perceived self-efficacy (5–25), five items of activity related affect (lowest score = 7 and highest score = 35), eight items of situational influences (8–40), 11 items of interpersonal influences (11–55), seven items of commitment to the plan of action (the lowest score = 7 and the highest score = 35), seven items of immediate competing demands and preferences (0–7) to measure the constructs of the model.

The items of the questionnaire were first prepared by using literature, and the validity was confirmed using content and face validity based on the opinions of 14 experts. The average content validity ratio (CVR) of all questions was 0.82 and the average content validity index (CVI) of questions was calculated to be 0.8. The reliability of the questionnaire was confirmed using test-retest method (with 5 days interval among 24 pregnant women) through the Interclass correlation coefficient (ICC) of 0.73. The Cronbach's alpha was calculated as 0.87 (33). The full text of the questionnaire is presented in the supplementary.

Non-consecutive three-day food records (3D-FRs).

A three-day food record was completed to evaluate calcium dietary intake at the beginning and end of the intervention. It was explained to pregnant women to include in this questionnaire everything that they have consumed during three days with an interval of every other day (two normal days and one day off). After converting the consumed raw and cooked ingredients into grams or milliliters, the data were analyzed to calculate the calcium using the nutritional software of Nutritionist IV and based on the food table of the United States Department of Agriculture, which was modified for Iranian foods (34) (35).

Procedure

Before starting the intervention, the objectives of the study were explained and pregnant women signed the informed consent form. The intervention group received three one-hour educational sessions with an emphasis on the food consumption and dairy groups based on the food pyramid and, the main ingredients of milk and dairy products, the importance of consuming milk and dairy products during pregnancy, how to consume milk and dairy products and the best time for their consumption, natural substitutes for milk and dairy products, and diseases related to insufficient consumption of milk and dairy products. Since the recommendation to intake calcium supplement is included in the routine care for pregnant women in Iran, the interventions and measurements of the amount of calcium intake solely focus on the behavior of calcium-rich food consumption, focusing on the consumption of milk and dairy products as the most available calcium-rich food. Women completed the questionnaires before, immediately after, and one month after the intervention (follow-up). We included the knowledge variable in addition to the Pender’s HPM.

Knowledge

In addition to holding three educational sessions along with providing pamphlets and educational videos, group discussion about the calcium needs of mothers during pregnancy and breastfeeding, and applying some assignments of searching the web to find scientific information about calcium-rich foods were used to improve women’s knowledge.

Furthermore, the following were implemented to improve each construct of the Pender’s HPM:

Perceived benefits

The benefits of calcium consumption was highlighted to improve the final behavior of consuming calcium-rich foods. The properties of calcium as one of the essential nutrients with very important structural, metabolic, and regulatory role in the body were explained to the participants, referring to calcium deficiency-related diseases, including preeclampsia, premature birth, low birth weight (LBW), and osteoporosis.

Perceived barriers

The method of replacing ingredients and the correct way of consuming dairy products were used to improve individuals’ perceived barriers. The best time to consume milk and dairy products is before sleep. While drinking a glass of milk at breakfast is recommended, the worst time to consume milk is at lunch. Some of the dairy substitutes include almond milk, coconut milk, soy milk, white beans, canned salmon, sardines, dried figs, Chinese cabbage, cowpeas, almonds, oranges, etc., which may be consumed if participants cannot consume milk.

Self-efficacy

In order to improve the self-efficacy of calcium consumption behavior, the following four strategies were used

A. Mastery experiences: Behavioral changes were implemented step by step to reach an optimal diet. In the case of vomiting induced by milk intake and for developing mastery experiences, a little amount of milk was first consumed and then, gradually increased to the optimal amount. Another way to improve calcium intake was to add calcium-rich foods to the diet several times instead of all at once.

B. Role modeling: women with successful models of milk consumption, who had inadequate calcium intake and milk intolerance at the beginning of their pregnancy were used as successful models of milk consumption.

She had finally overcomed to barriers of the milk consumption. She cooperated to guide participants during the intervention, providing her experiences. Mothers had the opportunity to discuss with the desired role model and raise their barriers.

C. Verbal persuasion and providing feedback: Verbal persuasion for each part of the behavior encouraged women to continue the behavior. After checking the mothers’ successful behavior at each stage, one or two motivational text messages were sent to women to persuade them. The educational materials were presented in group of women created in the WhatsApp. Some motivational feedbacks and the opportunity to apprise the challenge behavior were provided in this virtual group. In addition, direct verbal encouragements were done for the adopted behaviors of the mothers by the investigator.

D. Using relaxation techniques: A relaxation program was used to release the stress and tensions caused by doing behavior. This program included training various method for relaxation provided in the CD. The women were asked to present a report on how to implement this method. Possible issues while using these trainings were resolved in the next educational sessions. Necessary trainings were given to remove barriers.

Activity-related affects

Pender stated that activity-related affects influence individual's health-promoting behavior. Activity-related affect refers to positive or negative feelings on individual activity. This feeling causes people change or maintain their past behavior. In the present study, we introduced a various range of the replacement for each category of the calcium-rich products and tried to improve the fear of the consequences of unfollowing the diet, to influence the activity-related affects.

Interpersonal influencers

Since the access to women’s colleagues and peers, such as friends, etc. was not available in the same way for all mothers, the interventions related to the interpersonal influencers were only limited to the family and spouses. The spouses of the individuals were invited to provide the necessary supports in observing mother’s nutritional behavior. Spouses were participated through encouraging and sending text messages. They were invited to one of the educational sessions, with providing educational brochures on the behavior of calcium consumption. They were asked to avoid purchasing the foods competing with the consumption of milk and dairy products.

Competing influencers

pregnant women discussed about the ingredients of food or factors interfering with dairy and milk consumption. For example, the consumption of soft drinks containing artificial sweeteners with a negative effect on the consumption of milk and dairy products, is a competing influencer. Women contributed by providing solutions for each competing case and their consumption was followed up in each session.

Commitment to a plan of action

It is the concept of intention and identification of a planned strategy includes cognitive and behavioral processes, resulting in the implementation of health behavior.

The commitment to performing the challenging behavior of the person was intervened by discussing on the commitment and importance of continuing and keeping the behavior.

Immediate competing demands and preferences:

Competing demands are those alternative behaviors, interfering into consciousness which causes people have low control due to environmental contingencies like work or family care responsibilities. Women were asked about their desire to consume dessert and soft drinks and other demands competing with the consumption of milk and dairy products, and their opinions were heard and discussed.

Statistical analysis

The outlier variables were removed using SPSS software, Ver. 22 by Explore command. None of the variables related to Pender’s constructs had outliers. The difference of the amount of calcium intake before and after the intervention in three participants had outlier in the intervention group and were excluded from the analysis. The difference of the amount of calcium intake before and after the intervention had no outlier in the control group.

Standard Error of the Skewness and Kurtosis (between + 2 and − 2 values) were used to evaluate the normality of quantitative variables. After confirming the normality of the data, the independent sample t-test was used to measure the significant difference of normal quantitative variables, including income, gestational age, systolic blood pressure, and diastolic blood pressure, at the baseline. The Chi-square test was applied to assess the homogeneity of the classified quantitative variables, including age, parity, number of children, and nominal variables, including education, job, spouse’s education, and comorbidity between the control and intervention groups at baseline. The Mauchly's test of sphericity showed that the assumption of sphericity of the data is not met (p-value < 0.001).

Since the outcome variables included knowledge, perceived benefits, perceived barriers, perceived self-efficacy, activity-related affect, situational influences, interpersonal influences, situational influences, and commitment to a plan of action were measured after the intervention and one month after the intervention (follow up), repeated measure ANOVA test was employed to measure the effect of the intervention over time. First, the effect of the time was assessed independent of the effect of time. Then, the effect of groups was assessed independent of the effect of time. The final result of the test was evaluated in the form of interaction time × group.

Mauchly's test of sphericity validates the repeated measure ANOVA, which was performed before the test. If the significance level is less than 0.05, H₀ is rejected and H₁ is confirmed. If H₀ is rejected, the sphericity of the variance-covariance matrix of the dependent variable should be accepted and one of the Greenhouse Geisser, Haven-Flat, or lower limit tests should be used. These tests correct the degree of freedom and if H₀ of Mauchly's test is rejected, Greenhouse Geisser test is used in the present study.

Given that calcium consumption was measured only before and after the intervention and there was a significant difference in the amount of calcium intake at the baseline between the control and intervention groups, analysis of covariance test was used. The statistical significance level was considered as p-value < 0.05.

The mean age of women was 27.19 ± 6.3 in the control group and 30.77 ± 5.7 in the intervention group. The mean gestational age of mothers was 16.8 ± 3.2 in the control group and 16.4 ± 3.7 in the intervention group. The mean systolic blood pressure was 11.6 ± 0.8 and 11.2 ± 9.0 in the control and intervention groups, respectively.

Standard Error of Skewness and Kurtosis for the variables showed that the distribution of all variables at baseline, after intervention, and follow up was normal. The independent sample t-test revealed no significant difference in the variables of income, gestational age, systolic blood pressure, and diastolic blood pressure at baseline between the control and intervention groups. The difference in systolic blood pressure values was related to the decimal values of the mean blood pressure and the difference between two groups had no clinical value. In addition, there was no statistically significant difference between two groups at baseline (Table 1).

According to the Chi square test, there was no significant difference between the intervention and control groups in terms of the categorical demographic variables, including age ( > = 28 years and < 28 years), education (illiterate (33.3%), diploma and under diploma (66.6%), academic education (33.3%)), job (employed and unemployed), spouse’s education, number of children, parity, and comorbidities (hypertension, diabetes, and cancer) at baseline (P < 0.05) (Table 2).

Table 1

The comparison of quantitative variables in the intervention and control groups at baseline
variables	control	intervention	T-value	P-value
variables	SD ± mean	SD ± mean	T-value	P-value
calcium intake amount	185.88 ± 580.122	398.591 ± 732.15	2.016	0.05
Gestational age(week)	2.3 ± 8.16	3.7 ± 16.4	436.0	664.0
Income(toman)	09.1 ± 1.3	02.1 ± 6.2	526.0	071.0
Systolic blood pressure(mmhg)	8.0 ± 6.11	9.0 ± 2.11	9.1	057.0
diastolic blood pressure(mmhg)	7.0 ± 6.7	8.0 ± 2.7	9.1	050.0

Table 2

The demographic variables of pregnant women in the intervention and control groups at baseline
Variable / Group		Control N(%)	Intervention N (%)	P-value*
age	Age 28 >	16(44.4)	20(55.6)	0.346
age	Age 28 ≤	20(55.6)	16(44.4)	0.346
education	High school	10(41.7)	14(58.3)	0.075
	Diploma	16(69.9)	7(30.4)
	Bachelor degree and higher	(40)10	(60)15
job	Employed	10(62.5)	6(37.5)	0.257
job	Un-Employed	26(46.4)	30(53.6)	0.257
Spouse education	High school	(9/52)9	(1/47)8	739/0
	Diploma	(9/52)18	(1/47)16
	Bachelor degree and higher	(9/42)9	(1/57)12
parity	1	(1/32)9	(9/67)19	076/0
	2	(5/64)20	(5/35)11
	3	(8/53)7	(2/46)6
Number of children	1	(3/39)11	(7/60)17	102/0
	2	(6/63)21	(4/36)12
	3	(4/36)4	(6/63)7
comorbidity	no	(50)32	(50)32	645/0
comorbidity	yes	(4)50	(4)50	645/0
*The results from Chi-square test

The effect of the intervention regarding the calcium consumption behavior on the mean differences of each of the variables of the Pender’s model between two groups using independent sample t-test was as follows, respectively: the changes in the mean score of knowledge (P-value < 0.001; t = 4.20), changes in the mean score of perceived benefits (P-value < 0.001; t = 6.26), perceived barriers (P-value < 0.001; t = 6.87), perceived self-efficacy (P-value < 0.001; t = 3.56), activity-related affect (P-value < 0.001; t = 4.70), interpersonal influences (P-value = 0.20; t = 1.28), situational influences (P-value < 0.001; t = 3.19), commitment to a plan of action (P-value = 0.001; t = 4.08), and immediate competing demands and preferences (P-value < 0.001; t=-3.99) were significant before and after the educational intervention. However, the changes in the mean score of spouse’s social support, considered as interpersonal influences variable, were not significant before and after the intervention (P-value < 0.20; t = 1.28).

Muchly’s test for all of the studied variables, except for the variable of barriers demonstrated that H₀ about the sphericity of the variance-covariance matrix was rejected (P-value > 0.05). Therefore, the Greenhouse-Geisser correction test was used to correct the degree of freedom (df).

The results of the repeated measure ANOVA test at baseline indicated that the trend of changes independent of the effect of the two groups in the mean scores of knowledge (P-value = 0.001; F = 7.7), perceived benefits (P-value < 0.001; F = 38.2), perceived self-efficacy (P-value < 0.002; F = 6.4), activity-related affect (P-value < 0.001; F = 25.08), interpersonal influences (P-value = 0.043; F = 3.21), situational influences (P-value < 0.001; F = 12.82), commitment to a plan of action (P-value < 0.001; F = 25.43), and the construct immediate competing demands and preferences (P-value < 0.001; t =-3.99) were incremental and significant from baseline to after the intervention over time (Table 3).

Based on the results of the repeated measure ANOVA test, the studied variables were significantly different in the intervention and control groups without considering the effect of time. The construct of knowledge was significantly changed (P-value < 0.001, F = 17.15), and the constructs of perceived benefits (P-value < 0.001, F = 27.32), perceived barriers (P-value < 0.001, F = 67.39), perceived self-efficacy (P-value = 0.001, F = 11.97), activity-related affect (P-value < 0.001, F = 41.78), situational influences (P-value < 0.001, F = 24.96), interpersonal influences (P-value = 0.002, F = 10.21), commitment to a plan of action (P-value < 0.001; F = 14.32), immediate competing demands and preferences ( P-value < 0.001, F = 16.26) were significantly improved.

The interaction time × group effect was significant for all constructs of Pender’s HPM except for interpersonal influences construct. Table 3 illustrates the F- and P-value for the tests used for all constructs of Pender’s HPM.

Table 3

The changes in the variables related to the Pender’s HPM before and after the intervention and during the follow-up in the control and intervention groups.
Variable		baseline	After intervention		Follow up (one month)	p Time effect		P Group effect	F**		P-value**
		mean ± SD	mean ± SD		mean ± SD
knowledge	Intervention	2.6 ± 0.89	4.08 ± 1.3		4.02 ± 1.4	< 0.001		0.003	9.4^a		0.001
knowledge	control	2.4 ± 1.05	2.3 ± 1.5		2.5 ± 1.6	< 0.001		0.003	9.4^a		0.001
P-value*		0.473	0.001		0.001
Perceived benefits	Intervention	19.5 ± 1.5	22.08 ± 1.7		22.3 ± 2.08	< 0.001		0.001	17.24^b		0.001
Perceived benefits	control	19.5 ± 1.6	19.7 ± 1.4		20.4 ± 2.1	< 0.001		0.001	17.24^b		0.001
P-value*		0.940	0.001		0.001
Perceived barriers	Intervention	9.4 ± 1.2	6.8 ± 1.3		6.7 ± 1.3	< 0.001		0.001	40.8^a		0.001
Perceived barriers	control	9.5 ± 1.4	9.6 ± 1.1		9.5 ± 1.2	< 0.001		0.001	40.8^a		0.001
P-value*		0.791	0.001		0.001
Perceived self-efficacy	Intervention	13.2 ± 2.04	16.9 ± 4.9		16.02 ± 4.4	0.001<		0.005	10.90^a		0.001
Perceived self-efficacy	control	13.5 ± 4.1	13.08 ± 2.01		13.05 ± 2.2	0.001<		0.005	10.90^a		0.001
P-value*		0.718	0.001		0.001
Activity-related affect	Intervention	16.1 ± 4.4	18.3 ± 1.7		17.9 ± 1.7	< 0.001		0.001	14.85^a		0.001
Activity-related affect	control	15.5 ± 1.5	15.8 ± 1.2		15.6 ± 1.2	< 0.001		0.001	14.85^a		0.001
P-value*		0.059	0.001		0.001
Interpersonal influences	Intervention	38.6 ± 9.1	43 ± 8.2		42.2 ± 8.6	0.068		0.002	1.2^a		0.296
Interpersonal influences	control	35.5 ± 6.09	36.5 ± 9.8		36.3 ± 9.9	0.068		0.002	1.2^a		0.296
P-value*		0.171	0.001		0.001
Situational influences	Intervention	29.05 ± 4.3	33.1 ± 3.5		32 ± 3.5	< 0.001		0.001	21.51^a		0.001
Situational influences	control	27.9 ± 2.3	28.4 ± 5.7		26.9 ± 2.7	< 0.001		0.001	21.51^a		0.001
P-value*		0.089	0.004		0.010
Commitment to plan	Intervention	24 ± 3.9	29.1 ± 3.8		30.6 ± 5.3	0.001		0.001	20.2^a		0.001
Commitment to plan	control	25.2 ± 3.5	25.8 ± 2.2		25.5 ± 1.9	0.001		0.001	20.2^a		0.001
P-value*		0.154	0.001		0.001
Immediate competing demands and preferences	Intervention	3.80 ± 0.3	5.30 ± 0.18	4.9 ± 0.19		< 0.001	< 0.001			12.82^a	< 0.001
Immediate competing demands and preferences	control	3.63 ± 0.22	3.69 ± 0.22	3.58 ± 0.22		< 0.001	< 0.001			12.82^a	< 0.001
P-value*		0.14	0.001	0.001
*Independent sample t-test between intervention and control
*Tests of Within-Subjects Effects (interaction Time group)
a: Greenhouse–Geisser correction
b: Sphericity Assumed

Figure 1 displays the trend of changes in the constructs of Pender’s HPM in baseline, after intervention, and follow-up according to the control and intervention groups.

ANCOVA was used with adjustment of pre-test role to determine the effect of educational intervention based on Pender’s HPM on avarage calcium intake. The results showed that the intervention was effective and there is a significant difference in calcium intake between two groups (P < 0.001). (Table 4)

Table 4

The comparison of average calcium intake in the intervention and control groups
Variables	Sum of square	Degree of freedom (df)	Mean square	F	P-value
Pre-test effect	8769759.956	1	8769759.956	51.588	0.000
Independent variable effect	220712.109	1	220712.109	1.298	0.259
error	1.054E7	62
total	5.424E7	65

Educational intervention based on Pender’s HPM improve the constructs of Pender’s HPM (except social support) and calcium intake of mothers effectively. The mean score of knowledge and all of the constructs of the model improved except social support immediately after the and also one month after the intervention.

In the present study, knowledge was considered as a necessary variable for behavior change. The knowledge score of mothers in the intervention group was increased significantly compared to that of the control group immediately after the intervention. Further, the score of perceived benefits and perceived barriers improved after the intervention in the intervention group and remained at the optimal level in the intervention group during the follow-up. In addition, the barriers to calcium consumption were permanently removed among mothers over follow up time. Elselfi et al. (2020) in the application of Pender’s HPM stated that if the perceived benefits of breakfast consumption behavior increase among students and the perceived barriers to breakfast consumption decrease, subsequently the perceived self-efficacy for breakfast consumption will increase among students, which is consistent with the results of the present study (36). In a study, Vahedian Shahroodi et al. (2021) developed a clinical trial to improve physical activity and nutritional behavior among Iranian women. The perceived benefits and barriers of behavior based on Pender’s HPM in the intervention group were significantly improved compared to the control group after the educational interventions during the three- and six-month follow-up (37) Removing perceived barriers are an important factor in the process of self-care to perform healthy behaviors (38).

The self-efficacy improved with the four strategies applied in the study. The scores in the intervention group remained at the desired level during the follow-up. In another study, Vahedian Shahroodi et al. (2021) employed the strategy of using lecture, slides, teach-back video to improve self-efficacy. In addition, education for self-care and self-monitoring behaviors were used to increase the self-efficacy of mothers (37). In the same way, Grenny et al. (2013) reported that involving pregnant teenage mothers in cooking healthy foods motivates them to consume healthy foods (39). On the other hand, people with higher level of self-efficacy are more resilient in the face of behavioral barriers (40)

Bandura’s definition of self-efficacy also provided guidance in the development of this nutrition program. Bandura defined self-efficacy as individuals’ personal beliefs in their ability to organize and perform specific actions. Individuals’ personal beliefs (personal self-efficacy) determine how they motivate themselves and behave(41)According to pender’s health promotion model constructs, Perceived self-efficacy is base of human motivation, performance accomplishments, and emotional well‐being (Bandura, 1997, 2006). Also researches showed positive effect of education based on Pender model on self-efficacy and healthy behaviors in women with gestational diabetes mellitus(33)

Furthermore, Bandura suggested the strategies of mastery experiences, social modeling, social persuasion, and psychological responses to improve people’s self-efficacy. (42). Based on the results of the study Walker et al. (43) and von et al. (44), self-efficacy plays a predictive role in nutritional behaviors (45).

In the present study, the strategies of step-by-step behavior and breaking the behavior into small behaviors were used. Bandura stated that the modeling of successful people in the field of that behavior can be used to improve people’s self-efficacy. Accordingly, a successful pregnant woman in the field of consuming milk and dairy products and peer education as one of the appropriate methods for nutrition education were used. In the present study, pregnant women were asked to write down the suggested diet plan to promote calcium consumption and periodically share it on the WhatsApp platform and they were encouraged verbally. According to behaviorist theory, verbal persuasions cause reinforcement of the behavior performed in people. The strategy of relaxation and reassuring the person on continuing the calcium-rich food consumption behavior was used to improve possible tensions.

In the present study, the activity-related affect score increased after the intervention and during the follow-up, which had a significant difference with the control group. The behavior-related feeling in Pender’s PHM can explain 0.55 of the commitment to the behavior (46). Thus, feelings about performing a behavior, especially in behaviors related to nutrition, should not be ignored. In the study of Goodarzi-Khoigani et al. (53), there was a positive relationship between dairy consumption and Pender’s PHM and the educational intervention improved this relationship.

Since the consumption of milk as a calcium-rich source causes digestive problems for some mothers, they did not have a positive feeling toward its consumption before the intervention. These mothers were afraid of the consequences of consuming milk possibility of vomiting, which was resolved after the interventions.

Interpersonal influences are defined as cognitions concerning the behaviors, beliefs, or attitudes that decide individuals' predisposition to involve in healthy behaviors (47). The social support was considered as a measure of interpersonal influences. The results of the present study indicated that the social support of the spouse was not significant after the intervention. One of the reasons is that our intervention focused on the emotional support of the spouse, and other supports of the spouses, including financial, social, etc., were less investigated. Socio-cultural issues seem to affect behavior in a complex way and our interventions in this field was insufficient. Actually, cognitive and physiological factors may be more effective than the encouragement and support of the spouse in consuming calcium-rich foods, especially milk and dairy products, due to vomiting and lack of positive taste. The present study was in line with the study of Goodarzi-Khoigani et al. in the field of interpersonal influences in performing the desired behavior.

Perceived barriers and situational influences are predictive factors in relation to the commitment to plan of action (55). Consistent with the findings of Elseifi et al. (36) on breakfast consumption among students, the present study revealed that educational interventions, aimed at not consuming competitors and raising mothers’ knowledge of tempting situations to consume foods competing with calcium intake, can be effective until the follow-up period. However, some studies demonstrated no significant relationship between situational influences and oral health-related behaviors (48).

In this study, the commitment to the plan of action denoted an increase trend after the intervention and during the follow-up. Previous studies demonstrated that performing the related behavior significantly improves among pregnant women with greater commitment to the use of supplements. Based on the results of the early studies, the greater the commitment of pregnant mothers to the use of supplements, the more significant the associated behavior.

(49).

Commitment is the intention to perform healthy behaviors, including the identification of strategies to be able to conduct good health promotion behavior. Commitment will motivate people to adopt a healthy behavior despite obstacles encountered. In addition, internal locus of control leads to beliefs regarding one's actions with a causal association with the consequences. Therefore, people with internal locus of control can have more control over their behavior. Studies indicated that if dialysis patients and individuals who intend to quit smoking or lose weight have an internal locus of control, they can follow the instructions recommended by health care providers more than those who have an external locus of control (50). In the present study, since the interventions focused on empowering pregnant women regarding the behavior of consuming calcium-rich foods, probably these interventions could create an internal locus of control for individuals and increase their commitment to the implementation of the instruction.

In the present study, the desire of mothers to consume milk and dairy products as a source of calcium-rich food was in competition with the consumption of soft drinks, jam, ice cream, and delster. Previous studies demonstrated that interventions based on Pender’s HPM have been effective in the construct of immediate competitors (51), although the study of Dehdari et al. (2016) showed no significant change in this construct after the implementation of the intervention. In order to be effective intervention, programs should be focused on motivational programs across health care centers (52).

The use of the nutritional outcomes in addition to questionnaire data provided an opportunity to evaluate the effect of intervention based on the Pender’s HPM on clinical setting. In this study, randomization in the allocation of the pregnant women to intervention and control groups improved the possibility of controlling for confounders. All interventions were applied according to each construct of Pender’s HPM.

This study had some limitations, including using self-reported questionnaires for data collection, as the actual behavior of the pregnant women dose not observed, besides the recall bias for calculating the amount of the calcium intake. Further, given that the results are based on the convenience sampling method, the generalizability may be limited. Another limitation of this study may be the fact that our suggestion was focused on the diary intake rather than the all calcium-rich foods.

Based on the results, Pender's HPM can effectively improve the consumption behavior of foods containing calcium, such as milk and dairy products among pregnant women. All constructs of Pender's HPM, except for interpersonal influencers, showed a significant increase after the intervention and in a one-month follow-up period. The amount of calcium intake of mothers increased after the three-month intervention period by improving Pender’s HBM constructs. Pregnant women should be empowered to make healthy behaviors, and appropriate health education interventions should be developed. Therefore, the intervention framework of this study can be used in policy making of primary health care to promote nutritional behavior among pregnant women and other high-risk groups. Testing HPM is needed to support its predictive power in dairy behaviors. It also is suggested that health care providers use Pender’s HPM for other health-related behaviors.

Acknowledgement:

We would like to extend our special thanks to the Faculty of Health, Kermanshah University of Medical Sciences, and Vice-Chancellor of Research and Technology for allocating funds to this study.

Ethics approval and Consent to participate

Ethics approval was received from the ethics committee of deputy of research and technology, Kermanshah University of Medical Sciences (50000609).

This project has been approved by the Ethics Committee of Kermanshah University of Medical Sciences with ethical code IR.KUMS.REC.1398.468. The participants were fully informed about the purpose and nature of the study as well as their voluntary participation. They were reassured that their right to withdraw from the study without any prejudice, also the privacy and the confidentiality of all their data would be maintained. Before the start of the interview, conscious written informed consent was obtained from all the participants. Informed consent was obtained from the legal guardian of the Illiterate. If any of the questions caused distress for the participants, the interview was stopped, and after a while, and by the participant’s permission, it was continued. After the completion of an interview, the researcher was assured that the participants were not psychologically distressed in terms of the interview and that there was no need for immediate emotional support. At the end of the interviews, necessary information about the existing services for abused women was given to the participants, and they were referred to receive services, if necessary. Each participant was given a hypothetical code and name to keep their information confidential.

Consent for publication

All the participants gave their written informed consent to publish their direct quotes from interviews without their names

Competing interests

The authors declare that they have no competing interests

Authors' contributions

FR and NH designed the study. BM was involved in data collection. MR and MA finalized verbatim for the results. NH, FR, MR, BM and MA contributed to data analysis and interpretation. MA and FR wrote the draft of the manuscript while MR, NH did an extensive review of the manuscript. All authors reviewed and approved the final version of the manuscript.

Funding

This study funded by Vice-Chancellor of Research and Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable requests.

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No competing interests reported.

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The Effect of Educational Intervention based on Pender’s Health Promotion Model on Calcium Consumption among Pregnant Women

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Abstract

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Introduction

Method

Study design and participants

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Demographic characteristics questionnaire

Nutritional Behavior Questionnaire Based On Pender’s Health Promotion Model

Procedure

Activity-related affects

Immediate competing demands and preferences:

Statistical analysis

Results

Discussion

Limitation

Conclusion

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