Context: The Middle East has a high incidence of rickets and it is also common in Europe-dwelling children of Middle Eastern origin.

Obiective: To explore the mechanisms leading to rickets in children of the Middle East.

Design and Setting: We conducted a prospective study in 98 rachitic and 50 controls (age 6 mo – 4 yr) from university and community outpatient hospitals in Egypt and Turkey.

Main outcome measures: We collected epidemiological, maternal, nutritional, radiographic, and biochemical parameters, markers of bone turnover, and vitamin D receptor gene polymorphisms.

Results: Epidemiological factors had a key role in pursue of rickets; Egyptian and Turkish patients had lower (P < 0.01) dietary calcium intake than controls and the recommended dietary intakes (RDI), and serum 25-hydroxyvitamin D [25(OH)D] levels were reduced in patients, the difference with controls being significant (P < 0.001) only in Turkey, although rickets was more severe in Egypt as determined by the X-ray score (P < 0.05). In Turkey, the F VDR allele frequency was significantly (P < 0.05) increased in patients. The BB VDR genotype was associated with lower serum 25(OH)D levels in both patients and controls, and with severity of rickets.

Conclusions: In Turkey most patients had vitamin D deficiency, whereas in Egypt they had mostly calcium insufficiency combined with vitamin D deficiency. In this environ, VDR genotypes may predispose to rickets by increased frequency of the F allele. The unique environs and genetic predisposition have to be accounted for in the design of preventive measures, rather than using European or American RDI for calcium and vitamin D.