Vitamin D insufficiency in preadolescent African-American children.

To determine the proportion of vitamin D insufficiency in 6- to 10-year-old preadolescent African-American children residing in Pittsburgh, Pennsylvania and to estimate their therapeutic response to vitamin D 400 IU/day for 1-month, an open-label pre- and post-comparison of vitamin D status following vitamin D 400 IU daily for 1 month during winter and early spring was conducted. Outcomes included serum calcium, phosphorus, albumin, 25 hydroxyvitamin D [25 (OH) D], 1, 25 dihydroxyvitamin D [1, 25 (OH) (2) D], parathyroid hormone (PTH), and markers of bone turnover (serum bone-specific alkaline phosphatase, osteocalcin, and urine n-telopeptide crosslinked collagen type 1 [NTX]). Dietary intake of vitamin D was assessed using a food frequency questionnaire. Forty-one of the 42 enrolled subjects (mean age: 8.9 +/- 1.2 yrs [SD]) were analyzed, and 20/41 (49%) were vitamin D insufficient. Vitamin D insufficient group had a suggestive trend of being older (9.2 +/- 1.0 years vs. 8.5 +/- 1.3 years, p = 0.06) and more pubertally advanced (Tanner II: 7/20 vs. Tanner II: 1/21, p = 0.02). Mean dietary intake of vitamin D was 277 ( 146 IU/day (n = 41). Adequate intake for vitamin D (200 IU/day) was not met in 16/41 (39%); however, the dietary intake of vitamin D was not significantly different between the vitamin D insufficient and vitamin D sufficient groups.