Associations between Preserved Foods and Breast Cancer Risk in Hong Kong Chinese Women.

Preserved food such as cured foods may contain nitrate and nitrite that may contribute to the breast cancer development. Evidence on the associations between these preserved food intakes and risk of breast cancer is sparse. This study aimed to examine the associations between preserved foods (i.e., cured meat, pickled vegetables, canned meat, and canned fruit/vegetables) and breast cancer risk in Hong Kong Chinese women. A total of 1,307 breast cancer cases and 1,050 age-matched controls were recruited from three hospitals during November 2011 through January 2018. We used a standardized questionnaire to collect information on dietary factors, including preserved foods. Unconditional multiple logistic regression was performed to calculate the adjusted odds ratio (AOR) of breast cancer in relation to preserved food with adjustment of potential confounders. We further performed stratified analysis according to the breast cancer biology subtypes. We found that cured meat consumption was significantly associated with the risk of breast cancer [AOR, 1.32; 95% confidence interval 95% (CI), 1.06-1.64]. Compared with no cured meat consumption, cured meat intake ≥ once per week was associated with an AOR of 2.66 (95% CI, 1.38-5.35). Women with canned fruit/vegetable ≥ consumption once per week had a higher risk of breast cancer (OR, 1.19; 95% CI, 1.00-1.41), particularly for the HER2-positive subtypes, but it became borderline after adjustment of confounders. Our study reveals a positive association between consumption of cured meat and breast cancer risk in Chinese population. Cured meat intake might be a potential novel risk factor for breast cancer but this would have to be confirmed by large prospective cohort studies. PREVENTION RELEVANCE: The main finding of this case-control study, an association between cured meat intake and a higher risk of breast cancer in Hong Kong Chinese women, contributes to the growing evidence for population-level health benefits of reducing cured meat consumption.

Heterogeneous Associations Between Obesity and Reproductive-Related Factors and Specific Breast Cancer Subtypes Among Hong Kong Chinese Women.

Previous studies reported heterogeneous associations between obesity and reproductive-related breast cancer risk factors and breast cancer intrinsic subtypes; however, few studies have been conducted in Asian populations. Here, we aimed to examine whether risks associated with established breast cancer risk factors varied by breast cancer subtypes in Chinese women. We conducted a hospital-based case-control study in Hong Kong, including a total of 2169 Chinese women. Unconditional polytomous logistic regression models were used to calculate adjusted odds ratios (AORs) and 95% confidence intervals(95%CIs) to estimate relative risks associated with examined risk factors in case-control analyses and to test for heterogeneity across breast cancer subtypes in case-case analyses. In case-case analyses, compared with luminal A patients, luminal B (AOR = 1.76, 95% CI = 1.07-2.88), HER2 overexpressing (AOR = 3.40, 95% CI = 1.56-7.39), and triple negative (TNBC, AOR = 2.39, 95% CI = 1.18-4.82) patients were more likely to be postmenopausal. In case-control analyses, reduced risks associated with parity and younger age at first birth were only seen for luminal A and B cases especially among postmenopausal women, whereas having ≥ 3 children was associated with increased risk for HER2 overexpressing and TNBC among premenopausal women. Obesity was associated with increased risk for all subtypes. We found heterogeneous associations between parity-related risk factors by menopausal status and breast cancer subtypes among Chinese patients, which is similar to those observed in Western populations. Interestingly, obesity was associated with increased breast cancer risk regardless of menopausal status or subtypes, except for premenopausal luminal patients, which appears to be unique in Asian populations.

Nighttime eating and breast cancer among Chinese women in Hong Kong.

BACKGROUND: A novel line of research suggests that eating at nighttime may have several metabolic consequences that are highly relevant to breast cancer. We investigated the association between nighttime eating habits after 10 p.m. and breast cancer in Hong Kong women. METHODS: A hospital-based case-control study was conducted during 2012-2015. A total of 922 patients with incident breast cancer (cases) and 913 hospital controls were recruited and interviewed using a standard questionnaire including information on eating behavior during both daytime and nighttime. We collected the timing, duration, types and frequencies of food intake of eating at nighttime. Odds ratios (ORs) for the risk of breast cancer in relation to nighttime eating-related variables were calculated by unconditional multivariable logistic regression. RESULTS: Eating at night after 10 pm was significantly associated with breast cancer with an adjusted OR of 1.50 (95% confidence interval (CI) 1.06-2.12, P = 0.02), and the associations were stronger in women who had the longest duration of nighttime eating (≥20 years) (adjusted OR = 2.28 (95% CI 1.13-4.61, P = 0.02) and who ate late (midnight to 2 a.m.) (adjusted OR = 2.73, 95% CI 1.01-6.99, P = 0.04). Interestingly, nighttime eating was only associated with breast cancer among women who consumed staple foods (OR = 2.16, 95% CI 1.42-3.29, P < 0.001) but not those who ate vegetables or fruits as nighttime meals. The significant association between nighttime eating and breast cancer was observed among women with body mass index (BMI) <25 (OR = 2.29, 95% CI 1.48-3.52, P < 0.001) but not among women with BMI ≥25. CONCLUSIONS: Results from this study suggest a possible association between nighttime eating behavior and breast cancer. These findings need to be confirmed by independent large studies.

Evaluation of breast cancer risk associated with tea consumption by menopausal and estrogen receptor status among Chinese women in Hong Kong.

PURPOSE: Experimental studies implicate tea and tea polyphenols may be preventive against breast cancer, but evidence from epidemiological studies has been inconsistent. We conducted a hospital-based case-control study to evaluate the role of tea especially green tea in breast cancer etiology. METHODS: We consecutively recruited 756 incident breast cancer cases and 789 hospital controls who had completed information on tea consumption. We calculated odds ratios (ORs) for tea consumption using unconditional multivariable logistic regression. We further conducted stratified analyses to assess whether the effect of tea consumption varied by menopausal status and estrogen receptor (ER). RESULTS: Overall, 439 (58.1%) breast cancer cases and 434 (55.0%) controls reported habits of regular tea drinking, showing an adjusted OR of 1.01 (95%CI: 0.78-1.31) and 1.20 (95%CI: 0.80-1.78) for any tea and green tea drinking, respectively. Regular tea drinking was significantly associated with a lower risk for breast cancer in pre-menopausal women (OR=0.62, 95%CI: 0.40-0.97) but an increased risk in post-menopausal women (OR=1.40, 95%CI: 1.00-1.96). The positive association among postmenopausal women was strongest among ER-negative green tea drinkers (OR=2.99, 95% CI: 1.26-7.11). CONCLUSIONS: Tea or green tea drinking was not associated with overall breast cancer risk, which may be masked by the differential effect in pre- and post-menopausal women.

Familial risks and estrogen receptor-positive breast cancer in Hong Kong Chinese women.

PURPOSE: The role of family history to the risk of breast cancer was analyzed by incorporating menopausal status in Hong Kong Chinese women, with a particular respect to the estrogen receptor-positive (ER+) type. METHODS: Seven hundred and forty seven breast cancer incident cases and 781 hospital controls who had completed information on family cancer history in first-degree relatives (nature father, mother, and siblings) were recruited. Odds ratio for breast cancer were calculated by unconditional multiple logistic regression, stratified by menopausal status (a surrogate of endogenous female sex hormone level and age) and type of relative affected with the disease. Further subgroup analysis by tumor type according to ER status was investigated. RESULTS: Altogether 52 (6.96%) breast cancer cases and 23 (2.95%) controls was found that the patients' one or more first-degree relatives had a history of breast cancer, showing an adjusted odds ratio (OR) of 2.41 (95%CI: 1.45-4.02). An excess risk of breast cancer was restricted to the ER+ tumor (OR = 2.43, 95% CI: 1.38-4.28), with a relatively higher risk associated with an affected mother (OR = 3.97, 95%CI: 1.46-10.79) than an affected sister (OR = 2.06, 95%CI: 1.07-3.97), while the relative risk was more prominent in the subgroup of pre-menopausal women. Compared with the breast cancer overall, the familial risks to the ER+ tumor increased progressively with the number of affected first-degree relatives. CONCLUSIONS: This study provides new insights on a relationship between family breast cancer history, menopausal status, and the ER+ breast cancer. A separate risk prediction model for ER+ tumor in Asian population is desired.