Study area and period
This study was conducted at Azezo Health Center, Gondar, Northwest Ethiopia. It serves for a total population of more than 25000 individuals per year. The study was conducted from January 2017 to April 2017.
Study design: Institution-based comparative cross-sectional study design was employed.
Source and study population
All Depo-Provera users between 18-45 years of ages and the age matched non-Depo Provera users were the source population. Depo-Provera users between 18-45 years of age and age matched non-Depo Provera users who were present during the study period were the study population.
Inclusion and exclusion criteria
Women with chronic diseases like Diabetes mellitus and Hypertension and those who took medications known to affect body weight and blood pressure were excluded.
Sample size determination
The sample size for this study was determined by double-population formula: assuming 95% confidence interval, 80% power and by using the highest standard deviation. Systematic random sampling technique was used to select 50 healthy women who had been using Depo-Provera for at least six months and convenient sampling technique was used to recruit another 50 healthy age-matched (±2 years) controls who visited the health centers accompanying the patients during the study period.
Variables of the study
Dependent variable: Body weight, Body Mass Index and Blood Pressure.
Independent variables: Age, duration of use of Depo Provera
Data collection instrument and procedure
Structured pretested interviewer administered questionnaire was used to collect data. The questionnaire was prepared in English first and translated to Amharic and then, retranslated back to English by another person to check its consistency. Blood pressure was measured using recently calibrated standardized sphygmomanometer. The height measurement was also taken using stadiometer on flooring that is not carpeted and against a flat surface such as a wall with no molding and by removing the shoes, bulky clothing, hair ornaments, and unbraid hair that interferes with the measurement. The weight (Kg) of study participants was taken using a mechanical scale or balance.
The Mean Arterial Blood Pressure (MAP) was calculated by using the formula, MAP = Diastolic Blood Pressure (DBP) + 1/3(Systolic Blood Pressure-DBP). Body Mass Index (BMI) was computed by dividing weight (Kg) to the square of height in meter. The change in body weight, BMI and MAP of Depo-Provera users were calculated as the difference between initial body weight, BMI and MAP on the first day of injection, recorded by the health care providers and the final weight, BMI and MAP taken at their visit during study period.
Data quality control
Training was given for data collectors and pretest was also done. During data collection, data collectors were closely supervised by the supervisor and principal investigator on daily basis. Then after appropriate data clean up and correction was done just before analysis.
Data processing and analysis
Data were entered into Epi Data version 3.1 and exported to Statistical package for Social Sciences (SPSS) version 21 for analysis. Descriptive statistics such as mean, standard deviation (SD) and range were calculated. Paired t-test was used to evaluate change in body weight, BMI and blood pressure of Depo-Provera users. Independent t-test was also used to compare the results of blood pressure of Depo-Provera users and their age-matched control group. One-way ANOVA was used to identify the variation of variables in relation to the duration of use of Depo-Provera. Pearson’s correlation-test was used to evaluate the association between the variables. All values were quoted as the means ± SD, p-values of ≤0.05 were considered to be statistically significant.