Endemic Kashin-Beck disease: A food-sourced osteoarthropathy

Wang K, Yu J, Liu H, Liu Y, Liu N, Cao Y, Zhang X, Sun D · Seminars in Arthritis and Rheumatism

The closest thing to a natural experiment in nutrition and cartilage that exists. Kashin-Beck disease is an endemic osteoarthropathy of a narrow geographic band, and multivariate analysis attributes its cause to food-related factors — fungal contamination of grain, selenium deficiency, imbalanced protein intake. After preventive programmes reaching more than 300 million residents from the 1990s, national incidence fell from 22.1% in 1990 to 16.0% (1995), 12.3% (2000), 5.5% (2005), 0.38% (2010) and 0.18% in 2015. In 2016 it still affected 574,925 patients across a population of 22.6 million.

Population

National Chinese surveillance of Kashin-Beck disease, plus cross-sectional, case-control and intervention data

Intervention

Population-level preventive measures — selenium supplementation, grain replacement, water improvement, relocation

Comparator

The pre-intervention epidemic

Limitations

The preventive programmes changed several things at once — selenium, grain source, water, and in some areas where people lived — so the incidence collapse cannot be attributed to selenium alone, and the paper does not claim it can. Kashin-Beck disease is a growth-plate and articular-cartilage necrosis of childhood in deficient populations, not osteoarthritis; nothing here transfers to a replete adult.