
Probability of sexual debut

Number of sexual partners (per year)

Age at sexual debut


Covariate

Odds ratio

95%CI

pvalue

Incidence ratio

95% CI

pvalue

Hazard ratio

95% CI

pvalue


Intercept

0.61

(0.19, 1.96)

0.41

1.47

(0.98, 2.19)

0.06

–

–

–

Age (per year over 18)

1.48

(1.05, 2.14)

0.03

0.97

(0.89, 1.05)

0.42

0.88

(0.73, 1.07)

0.21

Female

0.85

(0.42, 1.68)

0.65

0.99

(0.82, 1.20)

0.94

0.90

(0.58, 1.42)

0.65

Race: white

1.78

(0.98, 3.27)

0.06

0.75

(0.63, 0.89)

0.001

1.51

(1.01, 2.28)

0.04

Alcohol: current drinker

2.73

(1.36, 5.56)

0.001

1.81

(1.36, 2.43)

<0.001

1.65

(0.98, 2.80)

0.06

Alcohol: binge drinker

1.71

(0.64, 5.12)

0.30

0.99

(0.79, 1.22)

0.92

1.34

(0.82, 2.22)

0.25

Marijuana: ever user

1.27

(0.60, 2.70)

0.53

1.06

(0.86, 1.32)

0.57

1.13

(0.73,1.75)

0.58

Vaccinated

At baseline

0.80

(0.41, 1.58)

0.52

0.81

(0.65, 1.00)

0.06

–

–

–

At sexual debut

–

–

–

–

–

–

1.27

(0.86, 1.87)

0.23

 The probability of sexual debut is analyzed by logistic regression; values are given as odds ratios (exponentiated model coefficients). The number of sexual partners is analyzed with Poisson regression with an offset of (the log of) number of years sexually active; values are incidence rate ratios (exponentiated model coefficients). The age at sexual debut is analyzed by a Cox proportional hazard model; results given as hazard ratios (exponentiated model coefficients). Boldface indicate p < 0.05. Study conducted in 2015–17, Ann Arbor, MI