Association between body mass index and risk of formation of breast cancer in Chinese women.
OBJECTIVE
To analyse the association between body mass index (BMI) and breast cancer risk among Chinese women in Hong Kong.


METHODS
We conducted a population-based case control study of breast cancer in June 2002. Standardized questionnaires concerning BMI and other anthropometric data were completed by patients at the Queen Mary Hospital (QMH). The cases were 198 women aged 24-85 years who had documented breast cancer in 1995-2000 by triple assessment criteria, and the controls were 353 women who were followed up at QMH for benign breast disease after breast cancer had been excluded by triple assessment. The controls were frequency-matched to the cases by age.


RESULTS
BMI at diagnosis was positively correlated with the risk of breast cancer among postmenopausal women (p < 0.001 for trend). Also, when compared with women with a low BMI (< 19), women with a BMI of 23-27 and 27-31 had a 1.73-fold (95% confidence interval, CI, 1.04-2.86) and 2.06-fold (95% CI, 1.08-3.93) increased risk of breast cancer, respectively, after adjustment for non-anthropometric risk factors. BMI at diagnosis, however, was not related to the risk of breast cancer among premenopausal women. The odds ratios for premenopausal women with a BMI of 23-27 and 27-31 were 1.5 (95% CI, 0.82-2.71) and 1.32 (95% CI, 0.39-4.43), respectively. Furthermore, present BMI and BMI 5 years before diagnosis were poorly associated with breast cancer risk among both pre- and postmenopausal women.


CONCLUSIONS
Weight control in obese women may be an effective measure for breast cancer prevention in postmenopausal women.
Chow
Louis W C
LW
Department of Surgery, University of Hong Kong, Hong Kong SAR, China. lwcchow@hkucc.hku.hk
Lui
Ka Luen
KL
Chan
Johnny Chun Yin
JC
Chan
Tuen Ching
TC
Ho
Po Ki
PK
Lee
Wing Yi
WY
Leung
Lik Hang
LH
Sy
Wing Man
WM
Yeung
Chin Chin
CC
Yung
Amy Ka Man
AK
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015897:Comorbidity; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D016017:Odds Ratio; D017698:Postmenopause; D017697:Premenopause; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D015996:Survival Rate