[Vitamin D nutrition in Chilean pre-school children living in extreme latitudes].

Background: Sunlight exposure is the main factor for adequate vitamin D (VitD) nutrition; in extreme latitudes there is an increased risk for its deficiency.

Aim: To study VitD nutritional status in pre-school children living in austral latitudes of Chile.

Subjects And Methods: A blood sample was obtained from 60 pre-school healthy children (aged 2 to 5 years, 24 males), attending to public day-care centers in Coyhaique (45° 35' S), during March (time 1) and September (time 2). 250 HD, parathyroid hormone (PTH), calcium, phosphate and alkaline phosphatases (PA) were measured. Information about weather conditions during three months prior to the sample withdrawal was gathered.

Results: Forty nine percent of children had a normal weight and 11% were overweight. Vive children with unreliable 250 HD levels were excluded from analysis. At time 1, 250 HD levels were 21.6 ± 14.5 ngl mh (7.9-71.1). Sixty four percent of children had valúes < 20 ng/mL (deficiency). At time 2, the figures were 21.5 ± 13.2 ng/mL (9.4-68.5) and 67.3% of children were deficient. PTH, serum calcium, phosphate and PA were normal. Prior to time 1, the UVradiation Índex (UVI) was high to extreme (91.3%), with 3.3 and 73% of sunny and cloudy days, respectively. Mean minimal and maximal temperatures were 7 and 17.3°C respectively. Prior to time 2 the IUVwas low in 100%) of days; with 15.2 and 60.9 of sunny and cloudy days, respectively. Mean minimal and maximal temperatures were 0.3 and 6.7°C respectively. No association of 250 HD with the other metabolicparameters was found.

Conclusions: Chilean pre-school children living in austral latitudes have a high rate of vitamin D deficiency, throughout the year, with no association with PTH, calcium, phosphate or PA. Further research is required to study vitamin D deficiency in other latitudes and magnitude of sunlight exposure.