The present study was undertaken to determine if a seasonal bias was present for vitamin D testing among Northeast Tennessee veterans, in whom vitamin D deficiency is common.
Medical chart review.
VA Medical Center.
Participants were 9447 patients with initial 25(OH) vitamin D levels obtained over a 3-year period.
Serum 25-hydroxyvitamin D (25[OH]D) level, date of testing, patient background factors.
Vitamin D testing occurred more frequently in September, October, November, and December, whereas the lowest levels of 25(OH) vitamin D levels were found in January, February, and March. Similar results were observed in quarterly data with the greatest number of tests noted in the last quarter of the year, yet the lowest 25(OH) vitamin D levels were noted in the first quarter. The average monthly 25(OH) vitamin D levels were below 30 ng/mL throughout the year in the study population, consistent with highly prevalent vitamin D deficiency.
Clinicians may have a seasonal bias, favoring testing for vitamin D status in the latter part of the year even though the lowest vitamin D levels are observed in the first part of the year. Although an argument could be made to check for peak 25(OH) vitamin D levels in September and trough levels in March, the seasonal contribution to vitamin D deficiency is overshadowed by ongoing vitamin D deficiency throughout the year. Thus, it may be prudent to test for vitamin D deficiency in patients presenting with fatigue, myalgias, and arthralgias regardless of the season of presentation.
To read this article in full you will need to make a payment
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to Journal of the American Medical Directors Association
Already a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
- Vitamin D deficiency.N Engl J Med. 2007; 357: 266-281
- The relationship of Vitamin D deficiency to health care costs in Veterans.Mil Med. 2008; 173: 1214-1218
- Plasma concentrations of 25-hydroxyvitamin-D3 (calcifediol) as an indicator of ultraviolet radiation.Arctic Med Res. 1993; 52: 166-169
- Influence of season and latitude on the cutaneous synthesis of vitamin D3: Exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin.J Clin Endocrinol Metab. 1988; 67: 373-378
- Time spent outdoors and seasonal variation in serum concentrations of 25-hydroxyvitamin D in Korean women.Int J Food Sci Nutr. 2000; 51: 439-451
- Contributions of vitamin D intake and seasonal sunlight exposure to plasma 25-hydroxyvitamin D concentration in elderly women.Am J Clin Nutr. 1994; 59: 80-86
- Seasonal changes in vitamin D status and bone turnover in healthy Irish postmenopausal women.Int J Vitam Nutr Res. 2007; 77: 320-325
- Seasonal variation of biochemical indexes of bone turnover: Results of a population-based study.J Clin Endocrinol Metab. 1998; 83: 68-75
- Seasonal diminution of vitamin D stores in the United States. Can darker winters lead to lighter bones?.Trends Endocrinol Metab. 1996; 7: 209-212
- Season of diagnosis is a predictor of cancer survival. Sun-induced vitamin D may be involved: A possible role of sun-induced Vitamin D.J Steroid Biochem Mol Biol. 2007; 103: 675-678
- The effects of seasonal variation of 25-hydroxyvitamin D on diagnosis of vitamin D insufficiency.N Z Med J. 2008; 121: 63-74
- Seasonal fluctuations in serum concentrations of vitamin D metabolites in normal subjects.BR Med J (Clin Res Ed). 1981; 282: 1349-1352
- Seasonal variance of 25-(OH) vitamin D in the general population of Estonia, a Northern European country.BMC Public Health. 2009; 9: 22
- Seasonal variation of maternal serum vitamin D in Newfoundland and Labrador.J Obstet Gynaecol Can. 2009; 31: 313-321
- Vitamin D deficiency and seasonal variation in an adult South Florida population.J Clin Endocrinol Metab. 2005; 90: 1557-1562
- Vitamin D insufficiency in southern Arizona.Am J Clin Nutr. 2008; 87: 608-613
- Seasonal variation in vitamin D levels in the Canterbury, New Zealand population in relation to available UV radiation.N Z Med J. 2007; 120 (U2733)
- The effects of season and stage of pregnancy on 25-hydroxy-vitamin D levels in pregnant women in Madrid.Int J Vitam Nutr Res. 1986; 56: 131-134
- Wintertime vitamin D deficiency in male adolescents: Effect on parathyroid function and response to vitamin D3 supplements.Osteoporos Int. 2001; 12: 875-879
- Vitamin D nutrition in relation to season and occupation.Am J Clin Nutr. 1981; 34: 1501-1504
- The high prevalence of vitamin D insufficiency across Australian populations is only partly explained by season and latitude.Environ Health Perspect. 2007; 115: 1132-1139
- Vitamin D status, seasonal variations, parathyroid adenoma weight and bone mineral density in primary hyperparathyroidism.Clin Endocrinol (Oxf). 2005; 63: 506-513
- Seasonal variation, hip fracture and vitamin D levels in Southern Tasmania.N Z Med J. 2002; 115: 183-185
- The dependency of vitamin D status on body mass index, gender, age and season.Anticancer Res. 2009; 29: 3713-3720
- Darkness at noon: Sunscreens and vitamin D3.Photochem Photobiol. 2007; 83: 459-463
- Wintertime vitamin D supplementation inhibits seasonal variation of calcitropic hormones and maintains bone turnover in healthy men.J Bone Miner Res. 2009; 24: 346-352
- Randomized comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients.Nutr J. 2004; 3: 8
- Serum 25 (OH)D3 vitamin status of elderly Finnish women is suboptimal even after summer sunshine but is not associated with bone density or turnover.Eur J Endocrinol. 2009; (In press)
- How to optimize vitamin D supplementation to prevent cancer, based on cellular adaptation and hydroxylase enzymology.Anticancer Res. 2009; 29: 3675-3684
Published online: January 13, 2010
Published by Elsevier Inc.