Purpose Nutritional rickets was initially thought to be prevalent in geographic areas with scarce sunlight. Cases of rickets have recently been reported from Texas, San Diego, Mississippi, Georgia and North Carolina. The purpose of this study was to identify cases of vitamin D deficiency rickets in Las Vegas, Nevada, which has approximately 310 days of sunshine a year.
Methods Inpatient and outpatient records from 1998 to 2002 from a 500-bed county hospital were obtained for children less than five years of age with the primary or secondary diagnosis of ‘rickets' and/or ‘hypocalcemia'. Premature babies, infants with chronic renal diseases, familial hypophosphatemia, hypocalcemia in the neonatal period and congenital and genetic abnormalities were excluded.
Results Five cases of rickets were identified. Ages of affected children varied from 7 months-2 years. Two children were born in Las Vegas, one in Alabama and one in California. All were Black, exclusively breastfed for 6 to 7 months and described as picky-eaters by their parents. They had resided in Las Vegas between 1 and 12 months. Other locations of residence included Alabama and California. The various diagnoses on presentation were hypocalcemic seizures, bulging of wrists and ankles, bowing of legs, limping and routine well child visit. Mothers of three children used daily prenatal vitamins and two continued vitamin use during lactation. None of the children received vitamin D supplements. Sun exposure varied from 20 minutes to 2 hours per week. Significant physical examination findings were bulging of wrists and ankles, bowlegs, rachitic rosary, frontal bossing and discrepant leg lengths. Laboratory findings in all children were suggestive of vitamin D deficiency rickets. Radiographic appearances of long bones were consistent with rickets. One child had a prolonged QTc interval. Treatment with calcium and vitamin D resulted in gradual resolution of all symptoms and signs.
Conclusions Vitamin D deficiency rickets can occur in perennially sunny Las Vegas if exclusively breastfeed infants are not supplemented with vitamin D. A published survey conducted as a follow-up to the detection of this case series revealed that 52.3% of healthcare providers in Las Vegas do not recommend vitamin D supplementation for exclusively breastfed infants, mainly due to the perception that supplementation is unnecessary in sunny climates. However, temperatures in Las Vegas in the summer can reach 117(F and may limit outdoor exposure.