An epidemiological model of privational rickets and osteomalacia.

Privational infantile rickets is now rare in the UK. Privational vitamin D deficiency remains common in the British Asian population, leading to neonatal, infantile and late rickets in childhood and osteomalacia (adult rickets) in Asian women (Dunnigan et al. 1962; Ford et al. 1972a, 1973; Holmes et al. 1973; Stamp et al. 1980). The prevalence of these manifestations of severe vitamin D deficiency in the Asian population has declined in the last 25 years. In the white population, privational osteomalacia is virtually confined to advanced old age (Gough et al. 1964; Anderson et al. 1966; Chalmers et al. 1967). The advent of privational Asian rickets and osteomalacia to Britain in the 1960s offered an opportunity to re-examine the environmental factors which determine these diseases. The present paper describes the development of a risk-factor model for Asian privational rickets and osteomalacia based on examination of the relative roles of limited exposure to U.V. radiation ( W R ) and dietary factors in their aetiology (Robertson e f al. 1982; Henderson et al. 1987, 1990). The model provides an explanation for trends in the prevalence of privational rickets and osteomalacia in the UK in the present century and for the current prevalence of these diseases in the UK and in many underdeveloped Third World countries where they remain common (Dunnigan et al. 1982).