Researchers from the University of Sydney report that vitamin D deficiency among Australians is more prevalent and lasts longer than expected.
The authors of the study collected 24,819 inpatient serum samples taken from the largest reference laboratory in New South Wales, Australia from July 2008 to July 2010. They took into account the effect of age, gender, season, and socioeconomic status.
The researchers found that Australians were most deficient during fall and spring, especially in September. Vitamin D levels were highest during the summer, peaking for women in January and men in February.
The researchers also found that women ages 20-39 are a high risk group for vitamin D deficiency. The authors call for further investigation of this finding.
Lead author Steven Boyages concludes:
“…Use of vitamin D supplements currently fail to address this factor of seasonal variation. A modified approach would see the use of supplements commence, or increase, at the end of summer and be maintained until the end of spring when they would either be stopped or reduced depending on an individual’s sunlight exposure.”