. 2020 May 26;23(14):2584–2601. doi: 10.1017/S1368980019005305

Table 1.

Characteristics of the included studies (39 studies and 45 records)

Study	Design, method	Country	Income level	Sample characteristics		Sample size	Sampling
Qualitative studies	Design, method	Country	Income level	Gender	Age (range)	n/households	Sampling
Batnitzky⁽¹⁸⁾	Field study, semi-structured interviews, observation	Morocco	Lower middle	Mixed	20+ years (adult)	1789	Unclear – individuals then households
Boatemaa et al. ⁽¹⁹⁾	Cross-sectional, interviews	Ghana	Lower middle	Mixed	15–35 years and 35+ years (adolescent and adult)	30	Purposive sampling
Brown et al. ⁽²⁰⁾	Cross-sectional, focus groups	Botswana	Upper middle	Mixed	12–18 years (adolescent) and adult (age range not specified)	72–132 (adolescents) parents unknown	Sampling of schools with differing tuition status
Craveiro et al. ⁽²¹⁾	Observational, focus groups	Cape Verde	Lower middle	Mixed	18–41 years (adult)	48	Opportunistic sampling using probabilistic sampling with random selection
Draper et al. ⁽²²⁾	Observational, focus groups	South Africa	Upper middle	Female	24–51 years (adult)	21	Convenience sampling
Legwegoh⁽²³⁾ and Legwegoh & Hovorka⁽²⁴⁾	Case-study, interview	Botswana	Upper middle	Mixed	20–65 years (adult)	40 households	Purposive sample, stratified based on household-head gender and socio-economic status
Rguibi & Behalsen⁽²⁵⁾	Cross-sectional, questionnaire via interview	Morocco	Lower middle	Female	15–70 years (adolescent and adult)	249	Convenience. Women visiting primary care centres
Sedibe et al. ⁽²⁶⁾ and Voorend et al. ⁽²⁷⁾	Observational, duo-interviews	South Africa	Upper middle	Female	15–21 years (adolescent)	58	Voluntary participation following researcher involvement in school
Quantitative studies
Agbozo et al. ⁽²⁸⁾	Cross-sectional, questionnaire	Ghana	Lower middle	Mixed	60–70 years (adult)	120	Purposive sample from four peri-urban communities
Amenyah & Michels⁽⁽²⁹⁾	Cross-sectional, questionnaire	Ghana	Lower middle	Mixed	11–18 years (adolescent)	370	Random selection, five secondary schools
Aounallah-Skhiri et al. ⁽³⁰⁾	Cross-sectional, questionnaire	Tunisia	Lower middle	Mixed	15–19 years (adolescent and adult)	1019	Clustered random sampling from three regions of Tunisia
Becquey et al. ⁽³¹⁾	Cross-sectional, questionnaire	Burkina Faso	Low	Mixed	15–65 years (adolescent and adult)	1072	Purposive random sampling
Cisse-Egbuonye et al. ⁽³²⁾	Quantitative, cross-sectional	Niger	Low income	Female	15–49 years (adolescent and adult)	3360	Randomly selected household heads in purposive sample
Codjoe et al. ⁽³³⁾	Cross-sectional	Ghana	Lower middle income	Mixed	15–59 years (adolescent and adult males), 15–49 years (adolescent and adult)	452 households	Purposive sampling according to age from a larger data set
El Ansari & Berg-Beckhoff⁽³⁴⁾	Cross-sectional, questionnaire	Egypt	Lower middle	Mixed	16–30 years (adolescent and adults)	2810	Voluntary questionnaire distributed to students attending lectures of randomly selected courses
Feeley et al. ⁽³⁵⁾	Cohort, questionnaire	South Africa	Upper middle	Mixed	13–17 years (adolescent)	1298	Cohort selection sampling-recruitment of all singleton births that occurred over a 7-week period in public delivery centres from all population groups
Fokeena & Jeewon⁽³⁶⁾	Cross-sectional, self-reported questionnaires	Mauritius	Upper middle	Mixed	12–15 years (adolescent)	200	Multistage sampling, schools randomly selected from four educational zones of Mauritius and sample taken from three of these schools
Glozah & Pevalin⁽³⁷⁾	Cross-sectional, self-reported questionnaires	Ghana	Lower middle income	Mixed	14–21 years (adolescent and adult)	770	Participants selected at random from four senior high schools that were purposively selected in Accra
Gitau et al. ⁽³⁸⁾	Longitudinal, self-reported questionnaire	South Africa	Upper middle	Males	13–17 years (adolescent)	391	Stratified convenience sample
Hattingh et al. ^(39,40,41)	Cross-sectional, questionnaire	South Africa	Upper middle	Female	25–44 years (adult)	488	Stratified random according to number of plots in each settlement
Jafri et al. ⁽⁴²⁾	Cross-sectional, questionnaire	Morocco	Lower middle	Female	18+ years (adult)	401	Multistage cluster. Households randomly selected within clusters
Kiboi et al. ⁽⁴³⁾	Cross-sectional, structured interviews, questionnaire	Kenya	Lower middle	Female	16–49 years (adolescent and adult)	254	Purposive sampling at antenatal clinic in a hospital over 1 month
Landais⁽⁴⁴⁾ and Landais et al. ⁽⁴⁵⁾	Cross-sectional, questionnaire	Morocco	Lower middle	Female	20–49 years (adult)	894	Multistage cluster. Households then addresses randomly selected from enumeration areas
López et al. ⁽⁴⁶⁾	Observational, 3 × 24 h dietary recalls	Morocco	Lower middle	Mixed	15–20 years (adolescent and adult)	327	All students enrolled in high schools year 2007–2008 completed survey
Mayén et al. ⁽⁴⁷⁾	Cross-sectional, survey	Seychelles	High	Mixed	25–64 years (adult)	2004	National surveys, random sample drawn from entire population
Mbochi et al. ⁽⁴⁸⁾	Cross-sectional, questionnaire	Kenya	Lower middle	Female	25–54 years (adult)	365	Stratified random according to number of women in each socio-economic stratum
Mogre et al. ⁽⁴⁹⁾	Cross-sectional, questionnaire	Ghana	Lower middle	Mixed	20–60 years (adult)	235	Stratified random based on number of employees in each department
Njelekela et al. ⁽⁵⁰⁾	Cross-sectional, questionnaire	Tanzania	Low	Mixed	45–66 years (adult)	209	Random stratified selection from list of adult residents, strata: gender
Onyiriuka et al. ⁽⁵¹⁾	Cross-sectional, structured questionnaire	Nigeria	Lower middle	Female	12–19 years (adolescent and adult)	2097	Random selection by ballot from four all-girls schools, no sampling performed as designed to include all students
Peltzer & Phaswana-Mafuya⁽⁵²⁾	Cross-sectional, survey	South Africa	Upper middle	Mixed	>50 years (adult)	3840	National population based sample, from original study (SAGE; two-stage probability sample)
Savy et al. ⁽⁵³⁾	Cross-sectional, questionnaire	Burkina Faso	Low	Female	29–50 years (adult)	481	Random, from a database containing an exhaustive list of inhabitants
Sodjinou et al. ^(54,55)	Cross-sectional, questionnaire	Benin	Low	Mixed	25–60 years (adult)	200	Multistage cluster. Neighbourhoods, households, then individuals randomly selected
Soualem et al. ⁽⁵⁶⁾	Cross-sectional, questionnaires	Morocco	Lower middle	Mixed	12–16 years (adolescent)	190	Random selection from five schools in Gharb region
Steyn et al. ⁽⁵⁷⁾	Cross-sectional, structured interview	South Africa	Upper middle	Mixed	≥16 years (adolescent and adult)	3287	Stratified sampling of annual survey data
Van Zyl et al. ⁽⁵⁸⁾	Cross-sectional, questionnaire	South Africa	Upper middle	Mixed	19–30 years (adult)	341	Convenience, residents of Johannesburg visiting a mall
Waswa⁽⁵⁹⁾	Cross-sectional, questionnaire	Kenya	Lower middle	Female	20–25 years (adult)	260	Stratified random according to university department size including each year
Zeba et al. ⁽⁶⁰⁾	Cross-sectional, questionnaires	Burkina Faso	Low	Mixed	25–60 years (adult)	110	Stratified random sampling, stratification by income
Mixed-methods
Charlton et al. ⁽⁶¹⁾	Cross-sectional, questionnaire; focus groups	South Africa	Upper middle	Female	Questionnaire: 17–50 years (adult and adolescent); Focus groups: 18–49 years (adult and adolescent)	Questionnaire: 394; focus groups: 39	Convenience, according to age and gender
Pradeilles⁽⁶²⁾	Cross-sectional, questionnaires; focus groups	South Africa	Upper middle	Mixed	Questionnaire: 17–19 years (adult and adolescent); Focus groups: 18 years+ (adult)	Questionnaire: 631; focus groups: 51	Cohort selection sampling-recruitment of all singleton births that occurred over a 7-week period in public delivery centres from all population groups; Snowball sampling