Table 1.
Results of meta-regression models for the influence of study and subgroup characteristics on prevalence estimates (risk scale)
| Study/subgroup characteristics | Number of observ-ations (studies)a | Unadjusted model | Mutually adjusted | |
|---|---|---|---|---|
| Risk difference (95 % confidence interval) p value | Risk difference (95 % confidence interval) p value | |||
| Gender | Men | 24 (17) | 1 | 1 |
| Women | 28 (20) | 0.010 (0.000, 0.020) p = 0.043 | 0.011 (0.001, 0.021) p = 0.031 | |
| Age | Under 20 | 24 (12) | 1 | 1 |
| Over 20 | 28 (15) | 0.013 (0.004, 0.023) p = 0.008 | 0.011 (0.000, 0.022) p = 0.048 | |
| Region | Europe | 44 (17) | 1 | 1 |
| Outside Europe | 8 (4) | 0.004 (−0.010, 0.018) p = 0.577 | 0.012 (−0.005, 0.030) p = 0.160 | |
| Response rate (per 10 % increase) | 52 (21) | 0.000 (−0.003, 0.003) p = 0.981 | 0.000 (−0.004, 0.004) p = 0.998 | |
| Study topic | General health | 9 (4) | 1 | 1 |
| Sexual health | 43 (17) | 0.009 (−0.004, 0.021) p = 0.165 | 0.010 (−0.006, 0.027) p = 0.208 | |
| Date | Before 2006 | 37 (17) | 1 | 1 |
| After 2006 | 15 (5) | −0.001 (−0.013, 0.011) p = 0.830 | 0.003 (−0.008, 0.015) p = 0.558 | |
| Number tested (per 1000 increase in sample) | 52 (21) | 0.001 (−0.003, 0.004) p = 0.775 | 0.000 (−0.004, 0.004) p = 0.985 | |
aThe number of studies adds to more than 21 for gender, age and date of study because some studies reported multiple prevalence estimates for these variables