title: Decreasing 25-hydroxy-vitamin D levels account for portion of the effect of increasing body mass index on breast cancer mortality.
abstract: METHODS
  Increased body mass index (BMI) and decreased serum vitamin D are both known to be associated with increased mortality from breast cancer. However, vitamin D levels are lower in obese individuals in general. Recent studies have sought to determine whether serum vitamin D levels can account for some of the association between higher BMI and increased risk for breast cancer and found that low vitamin D levels in the overweight and obese account for up to 40% of the BMI-attributable risk of developing breast cancer.
  
  
  RESULTS
  Here we reviewed the literature to determine if a similar relationship exists between vitamin D, BMI, and breast cancer mortality. Utilizing previously reported independent associations of low vitamin D and high BMI to increases in breast cancer mortality, as well as the known decrement in vitamin D per unit increase in BMI, we estimated that low vitamin D levels may be responsible for roughly 16% of the increased mortality from breast cancer in overweight and obese patients.
  
  
  CONCLUSIONS
  Although this is a relatively small proportion of the effect of obesity, supplements to increase serum vitamin D levels may represent a way to reduce obesity-associated disparities in breast cancer mortality.
authors.affiliation: Department of Family Medicine and Community Health, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Morton
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Thompson
mesh_terms: D015992:Body Mass Index; D001943:Breast Neoplasms / Q000097:blood / Q000150:complications / Q000401:mortality*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D009765:Obesity / Q000097:blood / Q000150:complications; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D