Study Participants
This is a population-based cross-sectional study. The study sample was derived from participants in the baseline survey of the ongoing Multimodal Interventions to delay Dementia and disability in rural China (MIND-CHINA), which targets people who were aged ≥65 years and living in the rural communities of Yanlou Town, Yanggu County, western Shandong Province, China. In March-September 2018, 5246 participants were examined as part of the baseline survey for MIND-CHINA. Of these, 220 (4.19%) were excluded due to missing data on CVH measurements, leaving 5026 persons for the current analysis.
The Ethics Committee of Shandong Provincial Hospital affiliated to Shandong University in Jinan, China reviewed and approved the protocol for MIND-CHINA. Written informed consent was obtained from all the participants, or in the case of cognitively impaired persons, from a proxy (usually a family member). MIND-CHINA was registered in the Chinese Clinical Trial Registry (registration no.: ChiCTR1800017758).
Data Collection and Assessments
The trained staff collected data via face-to-face interviews, clinical examinations, and laboratory tests following a structured questionnaire, which was developed and adapted from questionnaires used in the Study on Global Ageing and Adult Health (SAGE) and a local survey of aging and health.[20, 21] Data included demographic features (e.g., age, gender, and education), lifestyles (e.g., smoking, BMI, and physical activity), health history (e.g., hypertension, diabetes, and CVD), and use of medications in the last two weeks before the survey. Weight and height were measured with participants wearing light clothes and without shoes. BMI was calculated as weight (kg) divided by height squared (m2). After a 5-min rest, arterial blood pressure was measured on the right upper arm in a seated position using an electronic blood pressure monitor (HEM-7127J, Omron Corporation, Kyoto, Japan). We assessed physical activity via questions of frequency (e.g., daily, weekly, and monthly) and time (minutes) of walking, sports activities, and recreational activities. The frequency of physical activity was coded as 7, 1, and 1/4 for daily, weekly, and monthly activity, respectively, and physical activity was quantified as minutes spent per week by multiplying participation frequency with average minutes spent per time. Then we calculated the metabolic-equivalent of each activity according to the 2011 compendium of physical activities.[22] Peripheral blood samples were taken after an overnight fast, and blood samples were analyzed at the certified clinical laboratory of the local town health center. Fasting blood glucose (FBG) and total cholesterol (TC) were measured using an automatic biochemical analyzer (DIRUI CS-600B; DIRUI Corporation, Changchun, China).
Hypertension was defined as systolic pressure ≥140 mm Hg or diastolic pressure ≥90 mm Hg or current use of antihypertensive medication,[17] and high cholesterol as TC ≥6.22 mmol/L or having received treatment for high cholesterol,[18] diabetes as self-reported history of diabetes diagnosed by a physician or FBG ≥7.0 mmol/L or current use of blood glucose-lowering medication.[19] “Awareness” of a disease was referred to a self-reported physician diagnosis of the disease before the examination.[17] “Treatment” was referred to self-reported use of medications for a certain disease, and the treatment rate as the proportion of persons who were taking medications among people with the disease.[19] The control rate of hypertension, diabetes, and high cholesterol was defined as the proportion of achieving the goal of blood pressure <140/90 mm Hg,[17] TC <6.22 mmol/L,[18] and FBG <7.0 mmol/L,[19] respectively, among people who took the corresponding medications (control A) or among people who had the corresponding disease (control B).
Definition of Cardiovascular Health Metrics
We defined CVH metrics following the AHA’s recommendations,[5] with some modifications (Supplemental Table 1): (1) we did not include diet due to a lack of dietary data; (2) we defined ideal BMI as <24 kg/m2, as recommended for Chinese adults;[23] and (3) we defined ideal smoking level as never or quitting smoking >5 years.[24] Thus, we included six factors in the CVH metrics: smoking, BMI, physical activity, blood pressure, total cholesterol, and FBG. We considered smoking, BMI, and physical activity as behavioral CVH metrics, and blood pressure, total cholesterol, and FBG as biological CVH metrics. We categorized each of the six factors into three levels of poor, intermediate, and ideal. Participants with 0-2, 3-4, and 5-6 metrics at the ideal levels were defined as having poor, intermediate, and ideal global CVH metrics, respectively. [5] Furthermore, people with 0-1, 2, and 3 behavioral or biological CVH metrics at the ideal level were defined as having poor, intermediate, and ideal behavioral or biological CVH metrics, respectively.[14]
Statistical Analysis
Descriptive analysis was performed to report mean (standard deviation, SD) for continuous variables with normal distribution, and frequency (proportion) for categorical variables. Characteristics of the study participants by gender were compared using the chi-square test for categorical and t-test for normal distributed continuous variables. We reported the prevalence rate of individual and composite CVH metrics and the rates of awareness, treatment, and control of biological CVH components. IBM SPSS Statistics for Windows 22.0 (IBM Corp, Armonk, NY, USA) was used for all analyses. Two-tailed p<0.05 was considered to be statistically significant.