Circulating 25-hydroxyvitamin D and lung cancer risk and survival: A dose–response meta-analysis of prospective cohort studies

Lower serum level of 25-hydroxyvitamin D is associated with several negative outcomes. However, previous studies have indicated that 25-hydroxyvitamin D is associated with lung cancer risk and survival, but presented controversial results. PubMed and Embase databases were searched update to August 2017 to identify and quantify the potential association between 25-hydroxyvitamin D and lung cancer risk and survival. Seventeen eligible studies involving a total of 138,858 participants with 4368 incident cases were included in this meta-analysis. Our results showed statistically significant association between 25-hydroxyvitamin D and lung cancer risk and mortality. However, circulating 25-hydroxyvitamin D was not associated with overall lung cancer survival. Furthermore, compared with the lowest circulating 25-hydroxyvitamin D, the highest circulating 25-hydroxyvitamin D is significantly decreased risk of lung cancer risk in male and female. In addition, the highest circulating 25-hydroxyvitamin D was significantly associated with a lower risk in Caucasian and Asian. We also obtained the best fit at an inflection point of 10 nmol/L in piecewise regression analysis, increasing 10 nmol/L dose of circulating 25-hydroxyvitamin D was associated with an 8% reduction in the risk of lung cancer risk and an 7% reduction in the risk of lung cancer mortality. Subgroup meta-analyses in study quality, number of participants, and number of cases showed consistent with the primary findings. The highest circulating 25-hydroxyvitamin D was associated with decreased lung cancer risk and mortality but not overall survival