Supplementary Figure 4.

Coefficients (b) for the associations of sexual frequency with masturbation (yes vs no) across the quantile levels of sexual frequency, respectively. All coefficients and 95% CI were adjusted for demographic, socioeconomic, and epidemiological characteristics. The coefficients indicate the change in sexual frequency with 1-U increase in masturbation (yes vs no). Black line represent the estimated coefficients and the grey area represents 95% CI of the corresponding parameters calculated by QR model. Red solid line represents the estimated coefficients and two red dot lines represent 95% CI of each variables calculated by NB model. All coefficients and 95% CI were adjusted for demographic, socioeconomic and epidemiological characteristics.