title: Vitamin d deficiency and seasonal variation in an adult South Florida population.
abstract: Hypovitaminosis D is associated with impaired neuromuscular function, bone loss, and fractures. If a person is not taking a vitamin supplement, sun exposure is often the greatest source of vitamin D. Thus, vitamin D deficiency is not uncommon in the winter, particularly in northern latitudes. Our goal was to establish the prevalence of vitamin D deficiency in south Florida (U.S.), a region of year-round sunny weather. At the end of the winter, 212 men and women attending an internal medicine clinic at a local county hospital were enrolled for measurements of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, and PTH; 99 participants returned at the end of summer. The mean (+/-sd) winter 25(OH)D concentration was 24.9 +/- 8.7 ng/ml (62.3 +/- 21.8 nmol/liter) in men and 22.4 +/- 8.2 ng/ml (56.0 +/- 20.5 nmol/liter) in women. In winter, the prevalence of hypovitaminosis D, defined as 25(OH)D less than 20 ng/ml (50 nmol/liter), was 38% and 40% in men and women, respectively. In the 99 subjects who returned for the end of summer visit, the mean 25(OH)D concentration was 31.0 +/- 11.0 ng/ml (77.5 +/- 27.5 nmol/liter) in men and 25.0 +/- 9.4 ng/ml (62.5 +/- 23.5 nmol/liter) in women. Seasonal variation represented a 14% summer increase in 25(OH)D concentrations in men and a 13% increase in women, both of which were statistically significant. The prevalence of hypovitaminosis D is considerable even in southern latitudes and should be taken into account in the evaluation of postmenopausal and male osteoporosis.
authors.affiliation: Veterans Affairs Medical Center (11 GRC), 1201 NW 16 Street, Miami, Florida 33125, USA. slevis@med.miami.edu
authors.forename: Silvina
authors.initials: S
authors.lastname: Levis
authors.forename: Angela
authors.initials: A
authors.lastname: Gomez
authors.forename: Camilo
authors.initials: C
authors.lastname: Jimenez
authors.forename: Luis
authors.initials: L
authors.lastname: Veras
authors.forename: Fangchao
authors.initials: F
authors.lastname: Ma
authors.forename: Shenghan
authors.initials: S
authors.lastname: Lai
authors.forename: Bruce
authors.initials: B
authors.lastname: Hollis
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Roos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000378:metabolism; D005260:Female; D005431:Florida / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D014808:Vitamin D Deficiency / Q000453:epidemiology* / Q000503:physiopathology*