Study Design, Population and Recruitment
This was a community based cross-sectional study conducted between May and August, 2018 in an urban setting in Mwanza city, Tanzania. Mwanza has 2 universities, hosting a mixture of national and international students. Most young adults who are not students are involved in small-scale agriculture, fishing, and retail businesses or are employed in office jobs. Based on FINDRISC sensitivity of 82% in predicting unknown diabetes in a study done in Greece (reference), the minimum required sample size, adjusted for 10% non-response rate, was 252 participants. We recruited young adults who met the inclusion criteria of being in the age range of 18-35 years, not known to have the clinical diagnosis of diabetes or hypertension. Multistage random sampling technique was utilized where two wards from three urban districts (Nyamagana, Ilemela and Magu) were chosen and finally we chose four streets from each ward where participants were recruited. All participants provided written informed consent.
Data Collection
i) Participants Interview
Participants’ socio-demographic information were obtained using a structured questionnaire. Subsequently, the investigators also administered the FINDRISC questionnaire to all participants. The following parameters were recorded: age, level of physical activity, use of vegetables, history of high blood pressure, history of high blood glucose and family history of diabetes. The components of FINDRISC requiring measurements (body mass index and waist circumference) were evaluated as detailed in “clinical and anthropometric measurements” below. Each parameter was scored as per respective points assigned on the FINDRISC questionnaire. The individual scores were added to give a unit FINDRISC (Fin-score) for every participant. Risk categories were identified as per FINDRISC standard groups \of low risk, slightly elevated, moderate, high and very high risk.
ii) Clinical and Anthropometric Measurements
Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured two times at 5 minutes interval using a calibrated digital sphygmomanometer (CH-432B, Citizen Systems Japan Co Ltd). Mean Arterial Pressure (MAP) was calculated using the equation. Weight, height, hip and waist circumference were measured using a calibrated stadiometer and tape measure under WHO protocols. Body mass index (BMI) was calculated using the formula weight (kg)/Height2 (m2). BMI cut off for overweight and obesity were defined according to WHO standards.
iii) Biochemical Assessment
Upon completion of interviews, participants were instructed to fast overnight and were directed to report the next morning at nearby local government offices which were used as temporary research stations for assessment after an overnight fast (at least 8 hours). A capillary fingertip blood sample was obtained from each participant for fasting blood glucose using an ONCALL-PLUS device ((ACON Laboratories, Inc.). Assessment of glucose tolerance by Oral Glucose Tolerance Test (OGTT) was done by measuring blood glucose levels after administering 75mg of oral glucose mixed with 200mls of water, taken in 5 minutes. Two-hour postprandial capillary blood glucose was assessed using ONCALL-PLUS. Five milliliters (5mL) of venous blood was collected from consenting participants, processed and analyzed for plasma lipids under standard operating procedure (SOP) for lipid profile tests using ERBA XL machine (Erba Lachema s.r.o).
Definition of Clinical Parameters
Overweight was defined as BMI of 25kg/m2-30kg/m2; obesity as BMI> 30kg/m2; high waist to hip ratio as above 0.9 in males and 0.8 in females; dyslipidemia was defined as the presence of either total cholesterol of more than 5.2mmol/L, low density lipoprotein of more than 3.3mmol/L, triglycerides of more than 1.7mmol/L or high density lipoprotein of less than 1.03mmol/L in males or less than 1.29mmol/L in females; impaired glucose tolerance as OGTT capillary blood glucose levels of 7.8mmol/l to 11mmol/l; isolated systolic hypertension as systolic blood pressure of more than 140mmHg with normal diastolic blood pressure, isolated diastolic hypertension as diastolic blood pressure of more than 90mmHg with normal systolic blood pressure.
Statistical Analysis
Continuous variables were summarized into frequency, mean, standard deviations, median and inter-quartile ranges. Categorical variables were presented in frequency and proportions. Association between continuous variables was done using Pearson’s correlation. For clinical and biochemical parameters that are not featured in FINDRISC and which correlated significantly with FINDRISC, the predictive power of FINDRISC for these parameters was ascertained using linear regression. . Two-side P-values of equal or less than 0.05 were considered statistically significant. Data was analyzed using STATA IC 13 (64-bit; StataCorp LLC).
Ethical consideration.
Ethical clearance was sought from research and publication committee of MUHAS. Permission to conduct this study was obtained from Mwanza City director through regional medical officer. Each participant signed an informed consent before participation.