The influence of a breast cancer diagnosis on serum 25-hydroxyvitamin D.

The influence of a breast cancer diagnosis on serum 25-hydroxyvitamin D. Am J Epidemiol. 2019 Jan 04;: Authors: O'Brien KM, Sandler DP, House M, Taylor JA, Weinberg CR Abstract Prospective and retrospective studies of vitamin D and breast cancer have produced discrepant results. This may be due to variations in serum 25-hydroxyvitamin D [25(OH)D] concentrations over time, including systematic changes after breast cancer diagnosis. We measured total serum 25(OH)D in Sister Study participants who provided samples at baseline (2003-2009) and 4-10 years later (2013-2015). This included 827 women with an intervening breast cancer and 771 without. Although modestly correlated over time (R=0.42), 25(OH)D concentrations increased in both groups, with larger increases among cases (averaging 31.6 ng/mL at baseline, 43.5 ng/mL at follow-up) than controls (32.3 ng/mL at baseline, 40.4 ng/mL at follow-up). Consequently, the estimated association between 25(OH)D and breast cancer depended on whether baseline (odds ratio [OR]=0.87, 95% confidence interval [CI]: 0.78-0.98 per 10 ng/mL) or second blood draw measures (OR=1.17, 95% CI: 1.08-1.26 per 10 ng/mL) were used. Concentrations were related to regular (>4 times/week) vitamin D supplement use, which became more common over time. Increases were greater in cases (56% to 84%) than in controls (56% to 77%). Our results do not explain previously observed differences between retrospectiv...
Source: Am J Epidemiol - Category: Epidemiology Authors: Tags: Am J Epidemiol Source Type: research