Estimating gallstone incidence from prevalence data.

Because incidence data for gallstones are generally unavailable, we have used a previously described epidemiologic method to estimate age-specific incidence rates from published gallstone prevalence data in seven populations. Yearly incidence rates ranged from a low of 1 in 1000 for the younger men to 19 in 1000 for the oldest women. An overall pattern of increasing incidence of disease with increasing age was observed. Rate-ratios for oldest versus youngest subjects ranged from 4.0 in German women to 9.4 in Italian men: mean rate-ratio = 5.9; 95% CI = 4.0-7.8. For all centers, age-specific female incidence rates exceeded comparable age-specific male rates at all ages (mean female to male rate-ratio = 1.85; 95% CI = 1.7-2.0). No differences were observed in the sex-specific incidence of gallstones for subjects of similar age in the various centers (P = > 0.10). For Denmark our estimates resemble recently published incidence data obtained by re-surveying the original population.