Prevalence of Diseases and Statistical Power of the Japan Nurses' Health Study.

The article presents a study which investigates the prevalence of a past diagnosis of various diseases among 5-year age groups based on the Japan Nurses' Health Study (JNHS) cross-sectional baseline survey. Data obtained suggests that for all diseases, except ovarian cancer, the prevalence of a past diagnosis increased markedly with age and that incidence rates could be predicted based on the degree of increase in prevalence between two adjacent 5-year age groups.