1. Chronic alcoholism may be complicated by proximal muscle weakness associated with a selective atrophy of type II skeletal muscle fibres. The histopathological findings are non-specific as identical changes are seen in proximal muscle weakness associated with various metabolic myopathies, including osteomalacia. 2. The maximum voluntary contraction (MVC) of the dominant quadriceps and plasma 25-hydroxycholecalciferol [25-(OH)D] were measured in male alcoholics and control subjects to determine whether vitamin D deficiency contributed to proximal muscle weakness. 3. In both groups MVC declined with age and was related to body build. The distribution of plasma 25-(OH)D was skewed in alcoholics, with the mean significantly lower than in control subjects. Seventeen per cent of patients (but none of the control subjects) had pronounced biochemical deficiency [plasma 25-(OH)D < 10 nmol/l]. 4. Alcoholics were significantly weaker than control subjects, even after correcting for the effects of age, height and weight. The severity of associated liver disease (cirrhosis vs no cirrhosis) did not influence muscle strength. Variation in plasma 25-(OH)D and albumin made an insignificant contribution to the difference in MVC observed between patients and control subjects. 5. We conclude that proximal muscle strength is reduced in chronic alcoholism but that this is not due to associated vitamin D [25-(OH)D] deficiency or alcoholic cirrhosis.
1. The maximum voluntary isometric contraction (MVC) of the dominant quadriceps muscle was measured in 136 healthy White and 172 healthy Hindu Asian subjects resident in London, using a specially designed chair equipped with a force measuring load cell. 2. Males were stronger than females, and for both sexes MVC declined with age. From age 20 to 60 the annual decline in MVC ranged from 0.56% in White males to 1.5% in female Asians. 3. White subjects were stronger than Asian subjects even after correcting for the effect of age, height, weight and sex in a multi-factorial analysis. 4. Only in males did MVC correlate with height and weight. Asian women were more obese than any other group, and showed an increase in body mass index with age. 5. Twenty-two per cent of Asian subjects had marked vitamin D deficiency (plasma 25-hydroxycholecalciferol < 10 nmol/l). There was no correlation between MVC, and plasma 25-hydroxycholecalciferol.