Table 1. Characteristics of the included studies (39 studies and 45 records).
| Study | Design, method | Country | Income level | Sample characteristics | Sample size | Sampling/recruitment | |
|---|---|---|---|---|---|---|---|
| Qualitative studies | Gender | Age (threshold/range) | n/households | ||||
|
| |||||||
| Batnitzky, 2008(18) | Field study, semi-structured interviews, observation | Morocco | Lower middle | Mixed | 20+y (adult) | 1789 | Unclear - individuals then households |
| Boatemaa et al. (2018)(19) | Cross-sectional, interviews | Ghana | Lower middle | Mixed | 15-35y and 35+ y (adolescent and adult) | 30 | Purposive sampling |
| Brown et al. (2015)(20) | Cross-sectional, focus groups | Botswana | Upper middle | Mixed | 12-18y (adolescent) and adult (age range not specified) | 72-132 (adolescents) parents unknown | Sampling of schools with differing tuition status |
| Craveiro et al. (2016)(21) | Observational, focus groups | Cape Verde | Lower middle | Mixed | 18-41y (adult) | 48 | Opportunistic sampling using probabilistic sampling with random selection |
| Draper et al. (2015)(22) | Observational, focus groups | South Africa | Upper middle | Female | 24-51y (adult) | 21 | Convenience sampling |
| Legwegoh et al. 2012(23), 2016(24) | Case-study, interview | Botswana | Upper middle | Mixed | 20-65y (adult) | 40 households | Purposive sample, stratified based on household-head gender and socio-economic status |
| Rguibi and Behalsen, 2006(25) | Cross-sectional, questionnaire via interview | Morocco | Lower middle | Female | 15-70y (adolescent and adult) | 249 | Convenience. Women visiting primary care centres |
| Sedibe et al. (2014)(26); Voorend et al. (2013)(27) | Observational, duo-interviews | South Africa | Upper middle | Female | 15-21y (adolescent) | 58 | Voluntary participation following researcher involvement in school |
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| Quantitative studies | |||||||
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| Agbozo et al. (2018)(28) | Cross sectional, questionnaire | Ghana | Lower middle | Mixed | 60-70y (adult) | 120 | Purposive sample from four peri-urban communities |
| Amenyah et al. (2016)((29) | Cross-sectional, questionnaire | Ghana | Lower | Mixed | 11-18y (adolescent) | 370 | Random selection, 5 secondary schools |
| Aounallah-Skhiri et al. (2011)(30) | Coss-sectional, questionnaire | Tunisia | Lower middle | Mixed | 15-19y (adolescent and adult) | 1019 | Clustered random sampling from 3 regions of Tunisia |
| Becquey et al. (2010)(31) | Cross sectional, questionnaire | Burkina Faso | Low | Mixed | 15-65y (adolescent and adult) | 1072 | Purposive random sampling |
| Cisse-Egbuonye et al. (2017)(32) | Quantitative, cross sectional | Niger | Low income | Female | 15-49y (adolescent and adult) | 3360 | Randomly selected household heads in purposive sample |
| Codjoe et al. (2016)(33) | cross sectional | Ghana | Lower middle income | Mixed | 15-59y (adolescent and adult males), 15-49y (adolescent and adult) | 452 households | Purposive sampling according to age |
| El Ansari et al. (2015)(34) | Cross-sectional, questionnaire | Egypt | Lower middle | Mixed | 16-30y (adolescent and adults) | 2810 | Voluntary questionnaire distributed to students attending lectures of randomly selected courses |
| Feeley et al. (2013)(35) | Cohort, | South Africa | Upper middle | Mixed | 13-17 y (adolescent) | 1298 | Cohort selection sampling-recruitment of all singleton births that occurred over a seven week period in public delivery centres from all population groups |
| Fokeena et al. (2012)(36) | Cross-sectional, self-reported questionnaires | Mauritius | Upper middle | Mixed | 12-15y (adolescent) | 200 | Multistage sampling, schools randomly selected from 4 educational zones of Mauritius and sample taken from 3 of these schools |
| Glozah et al. (2015)(37) | Cross-sectional, self-reported questionnaires | Ghana | Lower middle income | Mixed | 14-21y (adolescent and adult) | 770 | Participants selected at random from 4 senior high schools that were purposively selected in Accra, Ghana. |
| Gitau et al. (2014)(38) | Longitudinal, self-reported questionnaire | South Africa | Upper middle | Males | 13-17y (adolescent) | 391 | Stratified convenience sample |
| Hattingh et al. 2006(39); 2011(40); 2014(41) | Cross-sectional, questionnaire | South Africa | Upper middle | Female | 25-44y (adult) | 488 | Stratified random according to number of plots in each settlement |
| Jafri et al. 2013(42) | Cross-sectional, questionnaire | Morocco | Lower middle | Female | 18+y (adult) | 401 | Multistage cluster. Households randomly selected within clusters |
| Kiboi et al. (2017)(43) | Cross-sectional, structured interviews, questionnaire | Kenya | Lower middle | Female | 16-49y (adolescent and adult) | 254 | Purposive sampling at Antenatal Clinic in a Hospital over 1 month |
| Landais 2012(44); Landais et al.(2014)(45) | Cross-sectional, questionnaire | Morocco | Lower middle | Female | 20-49 y (adult) | 894 | Multistage cluster. Households then addresses randomly selected from enumeration areas |
| Lopez et al. (2012)(46) | Observational, 3 x 24hr dietary recalls | Morocco | Lower middle | Mixed | 15-20y (adolescent and adult) | 327 | All students enrolled in high schools year 2007/2008 completed survey |
| Mayén et al. (2016)(47) | Cross-sectional, survey | Seychelles | High | Mixed | 25-64y (adult) | 2004 (1236) 2013 (1240) |
National surveys, random sample drawn from entire population |
| Mbochi et al. 2012(48) | Cross-sectional, questionnaire | Kenya | Lower middle | Female | 25-54y (adult) | 365 | Stratified random according to number of women in each socio-economic Stratum |
| Mogre et al. 2013(49) | Cross-sectional, questionnaire | Ghana | Lower middle | Mixed | 20-60y (adult) | 235 | Stratified random based on number of employees in each department |
| Njelekela et al. (2011)(50) | Cross-sectional, questionnaire | Tanzania | Low | Mixed | 45-66y (adult) | 209 | Random stratified selection from list of adult residents, strata: gender |
| Onyiriuka et al. (2013)(51) | Cross-sectional, structured questionnaire | Nigeria | Lower middle | Female | 12-19y (adolescent and adult) | 2097 | Random selection by ballot from 4 all-girls schools, no sampling performed as designed to include all students |
| Peltzer et al. (2012)(52) | Cross-sectional, survey | South Africa | Upper middle | Mixed | >50y (adult) | 3840 | National population based sample, from original study (SAGE; 2-stage probability sample) |
| Savy et al. 2008(53); | Cross-sectional, questionnaire | Burkina Faso | Low | Female | 29-50y (adult) | 481 | Random, from a database containing an exhaustive list of inhabitants |
| Sodjinou et al. 2008(54); 2009(55) | Cross-sectional, questionnaire | Benin | Low | Mixed | 25-60y (adult) | 200 | Multistage cluster. Neighbourhoods, households, then individuals randomly selected |
| Soualem et al. (2012)(56) | Cross-sectional, questionnaires | Morocco | Lower middle | Mixed | 12-16y (adolescent) | 190 | Random selection from 5 schools in Gharb region |
| Steyn et al. (2011)(57) | Cross-sectional, structured interview | South Africa | Upper middle | Mixed | ≥16y (adolescent and adult) | 3287 | Stratified sampling of annual survey data |
| Van Zyl et al. (2010)(58) | Cross-sectional, questionnaire | South Africa | Upper middle | Mixed | 19-30y (adult) | 341 | Convenience, residents of Johannesburg visiting a mall |
| Waswa, 2011(59) | Cross-sectional, questionnaire | Kenya | Lower middle | Female | 20-25y (adult) | 260 | Stratified random according to university department size including each year |
| Zeba et al. (2014)(60) | Cross-sectional, questionnaires | Burkina Faso | Low | Mixed | 25-60y (adult) | 110 | Stratified random sampling, stratification by income |
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| Mixed-methods | |||||||
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| Charlton et al. 2004(61) | Cross-sectional, questionnaire, ;fo cus groups | South Africa | Upper middle | Female | Questionnaire: 17-50y (adult and adolescent); Focus groups: 18-49y (adult and adolescent) | Questionnaire: 394; focus groups: 39 | Convenience, according to age and sex |
| Pradeilles (2015)(62) | Cross-sectional, questionnaires ; focus groups | South Africa | Upper middle | Mixed | Questionnaire: 17-19y (adult and adolescent); Focus groups: 18y+ (adult) | Questionnaire: 631; focus groups: 51 | Cohort selection sampling-recruitment of all singleton births that occurred over a seven week period in public delivery centres from all population groups ; Snowball sampling |