| 8 | Sasaki and Kameoka, [39] Year: 2009 Country: Hawaii Type of Study: Case-control study | Participants: Adolescents students Number: 4953 Female: 2491 Male: 2462 Age: ≤12 to ≥18years old | Data collection: Questionnaires Sampling methods: Purposive sampling Place: School-based | Determinants (risk behaviour) ・ Age ・ Ethnicity Risk factors ・ Lifetime sexual intercourse ・ Had sex before age 15 |
| 9 | Choi et al. [40] Year: 2013 Country: United States Type of study: Descriptive study | Participants: Adult MSM Number: 1196 Male: 1196 Age: 18 - 83 years | Data collection: Focus group discussion, in-depth interview Sampling methods: Snowball sampling Place: Community-based | Determinant ・ Ethnicity ・ Sex and Gender |
| 10 | Salud et al. [41] Year: 2014 Country: United States Type of study: Descriptive cross-sectional study | Participants: Young women Number: 299 Female: 299 Age: 18 - 24 years Mean age: 20 years, SD: 1.77 | Data collection: Questionnaires Sampling method: Purposive sample Place: Community-based | Determinants ・ Knowledge level ・ Sex and Gender Risk factors ・ Number of sexual partners ・ Sexually active |
| 11 | Lachowsky et al. [42] Year: 2014 Country: New Zealand Type of study: Cross-sectionals study | Participants: Younger MSM Number: 3352 Male: 3352 Age: 16 - 29 years Mean age: 23.2, SD: 3.5 | Data collection: Questionnaire Sampling method: Purposive sample Place: Community-based | Determinants (services) ・ Gender ・ Age ・ Ethnicity |
| 12 | Cruz et al. [43] Year: 2013 Country: Columbia Type of study: Retrospective study | Participants: Infants and pregnant women Number: 181 Infants: 89 Age: Preterm & term Female: 92 Age: 14 - 38; Mean: 23.6 | Data collection: Questionnaire Sampling methods: Simple Random sampling Place: Hospital-based | Determinants ・ Income ・ Age Risk factors ・ contracted STI |
| 13 | Han et al. [44] Year: 2014 Country: Australia Type of study: Cohort study | Participants: Younger and older HIV + patients Number: 7142 Male: 4278 Female: 2864 Age: <30 years to ≥60 years | Data collection: Questionnaire, observation Sampling methods: Purposive sampling Place: Hospital-based | Determinants ・ Age |
| 14 | Takahashi et al. [45] Year: 2006 Country: United States Type of study: Descriptive study | Participants: Women and youth Number: 313 Female: 313 Age: 15 to 24 years Mean age: 26 years
| Data collection: Questionnaire Sampling methods: Convenience sample Place: Community-based | Determinants ・ Sex and gender ・ Age |
| 15 | Kahle et al. [46] Year:2005 Country: United States Type of study: Cohort study | Participants: MSM, higher-risk heterosexuals and injection drug users young adults Number: 435 Male: 435 Age:18 - 30+ years | Data collection: Questionnaire Sampling method: Purposive sample Place: Community-based | Determinants ・ Perceptions Risk factors ・ Low level condom use ・ Injection drug use |
| 16 | Hahm et al. [47] Year: 2009 Country: United States Type of study: Prospective cohort study | Participants: Young female adults Number: 7576 Female: 7576 Age: 18 - 27 years | Data collection: Questionnaire Sampling method: Clustered sample Place: Community-based | Determinants (services) ・ Sex and Gender ・ Ethnicity
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