Systematic review of sexual problems: epidemiology and methodology.

We conducted a comprehensive systematic literature review of five sexual problems in order to estimate their population prevalence and to investigate issues arising from the reviewing of epidemiological literature. Two independent reviewers scrutinized abstracts, extracted data, and assessed methodological quality. Twenty-eight relevant studies were identified. Prevalence figures varied considerably, and meta-analysis was not possible because of heterogeneity in study quality and design. Prevalence depends on case definition, characteristics of the study population, and time frame of the prevalence estimates, therefore, design, implementation, and reporting of epidemiological studies needs standardization before systematic reviews and meta-analyses can be carried out.