Diagnosis of rickets and reassessment of prevalence among rural children in northern China.

BACKGROUND

Rates of rickets from 15.9 to 26.7% have been reported in China.

METHODS

Combining the methods of epidemiology and the behavioral sciences, this study investigated the prevalence of rickets in children in rural Shanxi Province, China. A total of 250 children age 12-24 months were examined physically for the presence of rickets, blood was drawn for laboratory analysis, and X-rays were taken of each child's wrists.

RESULTS

Vitamin D deficiency in the spring was found among 65.3% of children. Rickets diagnosis relying on clinical signs alone determined a rickets prevalence of 41.6%, declining to 17.0% in the fall after a summer of sun exposure (chi(2) = 8.356, P = 0.004). But an integrated diagnostic method exploiting clinical signs, X-ray and alkaline phosphatase levels found the prevalence of active rickets to be 3.7%. Furthermore, it was demonstrated that only five clinical signs reflect active rickets--wide wrists, frontal bossing, rachitic rosary, Harrison's sulcus, and bowed legs.

CONCLUSIONS

The prevalence of active rickets in young children in northern China is lower than previously reported. Even in poor countries, simple tests such as X-rays and alkaline phosphatase can be added to physical examination to more accurately diagnose active rickets.