This was a facility-based comparative cross-sectional study conducted from April 11 to May 11, 2019, in purposely selected health facilities in Jimma Town, Jimma zone, Oromia Regional State, southwest Ethiopia. The health facilities were Shenen Gibe General Hospital, Jimma Health Center, and Marie-Stopes International Clinic- Jimma, with a flow of 3136, 2328 and 2880 clients per year, respectively.
Women of reproductive age (15–49 years) who had been using DMPA for at least three months or implant for at least one month were targeted for inclusion in the study.
Women of reproductive age using the methods who had a history of chronic illness including diabetes, hypertension, liver dysfunction, cardiovascular disorders (CVD) and lipid profile and blood pressure (BP) affecting drug (including corticosteroids, antipsychotics, diuretics, anticonvulsants, retinoid, and antiviral) and breastfeeding mothers were excluded by reviewing their medical records and/or by asking. Women with suspected pregnancy were checked through rapid Human chorionic gonadotropin (HCG) test and those positive for HCG excluded from the study. Additionally, women with a family history of diabetes and hypertension, and women having physical deformity were excluded from the study.
Sample size determination
The sample size was determined by using G*power software version 3.1 for mean difference between two independent groups assuming a 5% level of significance (α) and 80% power (β) with an effect size greater than 0.5.
The mean and standard deviation of total cholesterol (TC) were taken from a study done in Addis Ababa , to calculate the minimum sample size for DMPA users. The procedure yielded a minimum sample size of 45 women, which was then proportionally allocated to each of the three health facilities as follows: 15 for Jimma Health Center, 7 for Marie Stopes International Clinic-Jimma Ethiopia, and 23 for Shenen Gibe General Hospital.
For implant users, the mean and standard deviation of Body Mass Index (BMI) were taken from a study done in Ghana , and the minimum sample size was 51. The sample size was proportionally allocated to each of the three health facilities as follows: 11 for Jimma Health Center, 26 for Marie Stopes International Clinic-Jimma Ethiopia, and 14 for Shenen Gibe General Hospital. A total of 50 women who did not use any of the contraceptives were selected as controls.
A systematic random sampling method was used to select each study participant by using an interval of 8 and 5 for DMPA and implant users respectively. Participants were recruited from women seeking services at the health facilities. Client flow data for each contraceptive method for the previous month were used to determine the sampling interval. Eligible participants were identified through interviews and review of medical records.
Data collection and measurement
Behavioral data (including Khat chewing, cigarette smoking, physical exercise, alcohol drinking and dietary habit) were collected using the WHO STEPS Questionnaire (available at https://www.who.int/ncds/surveillance/steps/instrument/en/) adapted to the local context based on the study objectives through face to face interview . The interviews were conducted by trained nurses in a room set aside for the study purpose in each health facility.
The height of the study participants was measured using a stadiometer (Seca, Germany) to the nearest 0.1 cm with the subjects positioned on the Frankfurt Plane. Before starting the measurements, the stadiometer was checked using calibration rods. Weight was measured using a digital glass weight scale to the nearest 0.1 kg with the subjects wearing light closes and shoes taken off. To check the validity of the scale, a known weight was measured every morning and in between the measurements . Waist circumferences were measured at the midway between the lowest costal margin at the midclavicular line and the anterior superior iliac spine using fixed tension tape, while hip circumference was measured at the level of the greater trochanter of the femur with the subjects wearing a pant .
All anthropometric measurements were done in triplicate and the average value was used for further analyses. Standardization exercise was done to reduce inter-observer error . BMI was calculated as the weight in kilogram (kg) divided by height in meters squared (kg/m2), and hip-to-waist ratio was calculated as the hip circumference in centimeter (cm) divided by waist circumference in cm.
Blood pressure measurement
Blood pressure was measured using Omron M2 Basic Blood Pressure Monitor with small, medium, and large cuff size, as appropriate for each participant, 15 min after the clients arrived at the facility. The subsequent measurements were done 5 min apart. Following the WHO recommendation, the mean systolic and diastolic blood pressure was considered for analysis .
Lipid profiles analysis
Fasting venous blood sample of five milliliter (ml) (after 8 h of fasting) was collected from the medial cubital vein of the left arm with a 19-gauge syringe (adult size) then transferred to a serum separator tube (SST) of 5 ml volume by experienced professional nurses. The blood drawing trial was performed at most two times. If the first trial failed, the unused arm was used for the second. When adverse events such as uncontrolled bleeding occurred, safety precautions were applied with respect to the standard guideline, and patient safety was assured by placing and stopping the bleeding using sterile gauze and banding at the site. Confidentiality of the participants information was kept by using code labels and no name was used to identify samples throughout the study process.
After the blood sample was collected, it was left at room temperature for 30 min until it became completely clotted. It was then kept in 2–8 °C refrigerator for no more than 8 h until prepared for storage. After blood was centrifuged at 3000 RPM for 5 min, the separated serum was stored at -80 °C with Nunc tube until analysis. Lipid profiles were analyzed from serum by Architect c4000 Automated Chemistry analyzer (Abbott, USA) at International Clinical Laboratory according to Standard Operating Procedure (SOP) from serum. Lipid profiles concentrations were reported as mg/dl.
Data analysis and presentation
Data were entered in Epidata version 188.8.131.52 and exported to IBM SPSS version 25 for analysis. One-way ANOVA was used to compare the mean of lipid profiles, blood pressure, anthropometric indices of DMPA users, implant users, and non-users (control). The Bonferroni post hoc test was used for multiple comparisons. A p value of < 0.05 was considered to be statistically significant. Pearson correlation was used to identify the association between outcome variables (anthropometric indices, blood pressure and lipid profiles) and the duration of DMPA and implant use. The normality and homoscedasticity of the data were checked by using the Shapiro–Wilk test and Levene’s test respectively. All values were reported as the means ± standard deviation (SD). The results are presented in charts, tables, and figures.
Data quality assurance
To ensure quality, the collected data were checked for completeness, accuracy, and clarity by data collection supervisors and the principal investigator. The principal investigator also ensured that source documents were maintained for each participant in the study comprising the investigator’s copy of the signed informed consent, behavioral and medical information, according to applicable good clinical practices (GCP) requirements. Data collectors were trained on how to approach study subjects, sample collection, handling of biological samples, and how to administer the questionnaire. Quality checking was done daily after data collection and amendments made before the next data collection.
All procedures for taking and analyzing biological samples were carried out by professionals. All laboratory procedures were carried out as per the approved protocol/ standard operating procedures (SOPs) of the laboratory.
Ethical and environmental considerations
Ethical clearance was obtained from Jimma University, Institute of Health Ethical Review Committee (reference number IHRPGD/553/2019). A support letter was obtained from the Health Research and Post Graduate director’s office for each study area. Written informed consent was obtained from participants over or equal to 18 years of age, while informed assent was obtained from study participants under the age of 18. Written informed consent were obtained from parents/guardians of participants below 18 years of age who visited the health facilities. All the participants’ information was kept confidential using the coding system and no direct benefit was provided for the participants except cost-free lipid profile analysis and blood pressure checkup.
Five ml of venous blood collection was drawn by experienced nurses following the standard operating procedure for venous blood collection developed by WHO . Those who were found to be positive for the measurements of this study were advised and linked to nearby health facilities for further evaluation. The used materials like syringe, gauzes, and leftover blood samples were disposed of according to the laboratory waste management protocol and incinerated.