Fat intake and breast cancer risk in an area where fat intake is low: a case-control study in Indonesia.

Background: Associations of fat and other macronutrients with breast cancer risk are not clear in areas where fat intake is low.

Methods: We conducted a hospital-based case-control study from 1992 to 1995 in Jakarta, Indonesia.

Results: The study, based on 226 cases and 452 age and socioeconomic status matched controls, provided the following findings. (a) In the pre-marriage period, the greater the fat or protein consumption, the larger the risk, whereas decreasing risk with increasing carbohydrate intake was detected. The odds ratio (OR) for the highest quartile of intake relative to the lowest was 8.47 (95% CI: 4.03-17.8) for fat, 2.19 (95% CI: 1.30-3.69) for protein, and 0.16 (95% CI: 0.08-0.31) for carbohydrate. A positive association with fat and a negative one with carbohydrate were also observed for the post-marriage period, but of weaker magnitude compared to the pre-marriage period. (b) The effects of macronutrient intakes were stronger among premenopausal than among postmenopausal women. (c) Most of the associations of protein and carbohydrate were insignificant after adjustment for fat intake.

Conclusions: These findings suggest that fat intake might be an important determinant of breast cancer among populations with a low fat diet in Indonesia.