The aim of this study was to evaluate the relation of nocturia, somatic diseases, symptoms, and medication to nocturnal giddiness in a group of elderly men and women. A questionnaire survey was undertaken among 10,216 elderly subjects. The mean (+/-S.D.) ages of the men and women were 73.0 +/- 6.0 and 72.6 +/- 6.7 years, respectively. Nocturnal giddiness was reported by 14.1% of the men and 9.1% of the women. Poor health was reported by 44.4% (P < 0.0001) of the men with nocturnal giddiness and by 14.0% of the men without, and among the women these figures were 45.5% and 20.0% (P < 0.0001), respectively. In a multiple logistic regression analysis significant independent correlates of nocturnal giddiness were: nocturnal micturition episodes >or=3 versus nocturia <or=2 (odds ratio [OR]: 1.6; 95% confidence interval [CI]: 1.1-2.3); married or cohabiting versus living alone (1.5; 1.1-2.0); age, 70-79 years versus <70 years (1.7; 1.2-2.3); age, >or=80 years versus <70 years (2.5; 1.7-3.6); eyesight, poor versus good (1.8; 1.4-2.4); hearing, poor versus good (1.4; 1.1-1.9); pain in the cervical spine (2.1; 1.5-2.8); spasmodic chest pain (1.5; 1.1-2.0); diabetes (1.6; 1.0-2.4); analgesics (1.8; 1.3-2.4); and diuretics (1.4; 1.1-21.8). Sex, irregular heartbeats, and sleep medication were deleted by the logistic model.