Does body fat distribution promote familial aggregation of adult onset diabetes mellitus and postmenopausal breast cancer?
Noninsulin-dependent diabetes mellitus and postmenopausal breast cancer share a number of risk factors, including obesity, increased waist-to-hip ratio, and a positive family history. If risk for these diseases is mediated through a familial tendency for abdominal obesity, then one might expect to see familial clustering of both diseases. We analyzed data from a prospective cohort study of 41,837 Iowa women age 55-69 years. Diabetes was not associated with incidence of breast cancer [relative risk (RR) = 0.97]. The association between family history of breast cancer and breast cancer incidence, however, was slightly modified by individual history of diabetes: a positive family history of breast cancer in the absence of baseline diabetes was associated with a relative risk of 1.36 [95% confidence interval (CI) = 1.08-1.70], whereas the presence of both factors was associated with a RR of 1.87 (95% CI = 0.93-3.76). Adjustment for waist-to-hip ratio greatly diminished this difference. Conversely, a family history of breast cancer was associated with a RR of 5-year diabetes mortality of 1.94 (95% CI = 1.17-3.24) that persisted after stratification by tertile of waist-to-hip ratio. No clear association of family history of breast cancer and waist-to-hip ratio for self-reported diabetes incidence was evident. These data are indicative of a complex interrelation between waist-to-hip ratio, familial predisposition, diabetes, and breast cancer.
Sellers
T A
TA
Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis 55454.
Sprafka
J M
JM
Gapstur
S M
SM
Rich
S S
SS
Potter
J D
JD
Ross
J A
JA
McGovern
P G
PG
Nelson
C L
CL
Folsom
A R
AR
D000273:Adipose Tissue; D000368:Aged; D001824:Body Constitution; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D006801:Humans; D015994:Incidence; D007484:Iowa / Q000453:epidemiology; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D017698:Postmenopause; D011446:Prospective Studies; D012307:Risk Factors