Obesity is a causal factor in vitamin D deficiency, but vitamin D deficiency does not lead to any significant weight gain, according to a multicenter, genetic study.

"While many health messages have focused on a lack of sun exposure or excessive use of suncreams, we should not forget that vitamin D deficiency is also caused by obesity," lead author Elina Hypponen, PhD, from the Institute of Child Health at University College London, United Kingdom, said in a news release.

"Our study highlights the importance of monitoring and treating vitamin D deficiency in people who are overweight or obese, in order to alleviate adverse health effects caused by a lack of vitamin D."

To evaluate the association between body mass index (BMI) and genes linked to vitamin D synthesis and metabolism, the researchers used genetic markers identified by analyzing 21 cohort groups that enrolled up to 42,024 participants for the D-CarDia Collaboration. The researchers confirmed associations between vitamin D and BMI using data from the Genetic Investigation of Anthropometric Traits (GIANT) consortium, which enrolled up to 123,865 participants.

"This study suggests that obesity could cause vitamin D deficiency," Dr. Hirschler said. "However, low vitamin D levels did not [appear to be] a causal factor in the development of obesity."