OBJECTIVES: To investigate whether caffeine intake is associated with urinary incontinence (UI) among Japanese adults. METHODS: A total of 683 men and 298 women aged 40 to 75 years were recruited from the community in middle and southern Japan. A validated food frequency questionnaire was administered face-to-face to obtain information on dietary intake and habitual beverage consumption. Urinary incontinence status was ascertained using the International Consultation on Incontinence Questionnaire-Short Form. RESULTS: Mean daily caffeine intake was found to be similar between incontinent subjects (men 120 mg, women 94 mg) and others without the condition (men 106 mg, women 103 mg), p=0.33 for men and p=0.44 for women. The slight increases in risk of UI at the highest level of caffeine intake were not significant after adjusting for confounding factors. The adjusted odds ratios (95% confidence interval) were 1.36 (0.65 to 2.88) and 1.12 (0.57 to 2.22) for men and women, respectively. CONCLUSIONS: No association was evident between caffeine intake and UI in middle-aged and older Japanese adults. Further studies are required to confirm the effect of caffeine in the prevention of UI.
Adult ; Aged ; Caffeine/*administration & dosage/*adverse effects ; Female ; Health Surveys ; Humans ; Japan/epidemiology ; Male ; Middle Aged ; Odds Ratio ; Questionnaires ; Risk Assessment ; Urinary Incontinence/*chemically induced/*epidemiology/physiopathology

Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.
Humans ; Lung Neoplasms/*etiology/prevention & control ; Risk Assessment ; Tea/*adverse effects