Correlates of 25-hydroxyvitamin D among Chinese breast cancer patients.
BACKGROUND
Few studies have investigated vitamin D status in association with modifiable lifestyle factors and clinical characteristics among breast cancer patients, with no studies among Chinese women, who may be at higher risk of vitamin D deficiency. We aimed to evaluate circulating 25-hydroxyvitamin D (25(OH)D) levels in association with clinical and lifestyle factors among 1,940 Chinese breast cancer patients.


METHODS
Participants included breast cancer cases aged 22-77 from a population-based case-control study conducted in Shanghai, China during 1996-1998 (n = 1,044) and 2002-2005 (n = 896). Circulating 25(OH)D levels were measured in plasma samples (95% collected ≤6 months post-diagnosis). Prevalence ORs and 95% CIs were derived from multinomial logistic regression models, adjusting for age, season, and other factors.


RESULTS
About 23% and 48% of women were vitamin D deficient (<30 nmol/L) or insufficient (30-50 nmol/L), respectively. Tumor characteristics were not associated with vitamin D status. Higher BMI was associated with increased odds of vitamin D deficiency (ORs (95% CIs): 1 (reference), 1.12 (0.85,1.47), and 1.57 (1.02,2.42), for <23, 23-<27.5, and ≥27.5 kg/m(2), respectively, Ptrend <0.06). Total physical activity was associated with reduced odds of vitamin D deficiency (ORs (95% CIs):1 (reference), 0.84 (0.59,1.20), 0.65 (0.45,0.93), and 0.69 (0.48,1.00), for <7.65, 7.65-<10.6, 10.6-<13.5, ≥13.5 MET-hours/day, respectively, Ptrend <0.02). Smoking was associated with vitamin D insufficiency and deficiency (ORs (95% CIs): 2.50 (1.07,5.84) and 2.78 (1.11,6.95), respectively).


CONCLUSIONS
In the largest study to date, the prevalence of low vitamin D status was high among Chinese breast cancer patients and associated with higher BMI, smoking, and lower physical activity. Our findings support careful monitoring of vitamin D status and recommendations for supplementation and other lifestyle modifications that may improve vitamin D status in breast cancer patients.
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America ; Department of Diabetes Control and Prevention, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China.
Liang
L
Shi
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Sarah
S
Nechuta
Department of Epidemiology, Shanghai Cancer Institute, Shanghai, China.
Yu-Tang
YT
Gao
Department of Cancer Prevention & Control, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China.
Ying
Y
Zheng
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Tsogzolmaa
T
Dorjgochoo
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Jie
J
Wu
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Qiuyin
Q
Cai
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Wei
W
Zheng
Department of Cancer Prevention & Control, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China.
Wei
W
Lu
Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
Xiao Ou
XO
Shu
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000097:blood* / Q000150:complications*; D016022:Case-Control Studies; D002681:China; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000209:etiology*; D055815:Young Adult
D014807:Vitamin D; C104450:25-hydroxyvitamin D