Higher diet-dependent acid load is associated with risk of breast cancer: Findings from the sister study.

Dietary factors that contribute to chronic low-grade metabolic acidosis have been linked to breast cancer risk, but to date no epidemiologic study has examined diet-dependent acid load and breast cancer. We used data from 43,570 Sister Study participants who completed a validated food frequency questionnaire at enrollment (2003-2009) and satisfied eligibility criteria. The Potential Renal Acid Load (PRAL) score was used to estimate diet-dependent acid load. Higher scores reflect greater consumption of protein and phosphorus, and lower consumption of potassium, calcium and magnesium. The association between PRAL and breast cancer was evaluated using multivariable Cox proportional hazards regression. We identified 1,614 invasive breast cancers diagnosed at least 1 year after enrollment (mean follow-up, 7.6 years). The highest PRAL quartile, reflecting greater acid-forming potential, was associated with increased risk of breast cancer (HRhighest vs. lowest quartile : 1.21 [95% CI, 1.04-1.41], ptrend = 0.04). The association was more pronounced for estrogen receptor (ER)-negative (HRhighest vs. lowest quartile : 1.67 [95% CI, 1.07-2.61], ptrend = 0.03) and triple-negative breast cancer (HRhighest vs. lowest quartile : 2.20 [95% CI, 1.23-3.95], ptrend = 0.02). Negative PRAL scores, representing consumption of alkaline diets, were associated with decreased risk of ER-negative and triple-negative breast cancer, compared to a PRAL score of 0 representing neutral pH. Higher diet-dependent acid load may be a risk factor for breast cancer while alkaline diets may be protective. Since PRAL scores are positively correlated with meat consumption and negatively correlated with fruit and vegetable intake, results also suggest that diets high in fruits and vegetables and low in meat may be protective against hormone receptor negative breast cancer.

Long-Term Satisfaction and Body Image After Contralateral Prophylactic Mastectomy.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) rates have been increasing in the US, and although high levels of satisfaction with CPM have been reported, few studies have evaluated the long-term effects on body image, comparing CPM with breast-conserving surgery (BCS) and unilateral mastectomy (UM). METHODS: We analyzed responses from a survey of women with both a personal and family history of breast cancer who were enrolled in the Sister Study (n = 1176). Among women who underwent mastectomy, we examined satisfaction with the mastectomy decision, as well as variation in the use of reconstruction and experience of complications. Five survey items, evaluated individually and as a summed total score, were used to compare body image across surgery types (BCS, UM without reconstruction, CPM without reconstruction, UM with reconstruction, and CPM with reconstruction). RESULTS: Participants were, on average, 3.6 years post-diagnosis at the time of survey (standard deviation 1.7). The majority of women (97% of CPM, 89% of UM) were satisfied with their mastectomy decision. Reconstruction was more common after CPM than after UM (70 vs. 47%), as were complications (28 vs. 19%). Body image scores were significantly worse among women who underwent CPM than among women who underwent BCS, with the lowest scores among women who underwent CPM without reconstruction. CONCLUSIONS: In our sample, most women were highly satisfied with their mastectomy decision, including those who elected to undergo CPM. However, body image was lower among those who underwent CPM than among those who underwent BCS. Our findings may inform decisions among women considering various courses of surgical treatment.

Indoor wood-burning from stoves and fireplaces and incident lung cancer among Sister Study participants.

BACKGROUND AND AIM: Epidemiological studies conducted mostly in low- and middle-income countries have found a positive association between household combustion of wood and lung cancer. However, most studies have been retrospective, and few have been conducted in the United States where indoor wood-burning usage patterns differ. We examined the association of exposure to indoor wood smoke from fireplaces and stoves with incident lung cancer in a U.S.-wide cohort of women. METHODS: We included 50,226 women without prior lung cancer participating in the U.S.-based prospective Sister Study. At enrollment (2003-2009), women reported frequency of use of wood-burning stoves and/or fireplaces in their longest-lived adult residence. Cox regression was used to estimate adjusted hazard ratios (HRadj) and 95 % confidence intervals (CI) for the association between indoor wood-burning fireplace/stove use and incident lung cancer. Lung cancer was self-reported and confirmed with medical records. RESULTS: During an average 11.3 years of follow-up, 347 medically confirmed lung cancer cases accrued. Overall, 62.3 % of the study population reported the presence of an indoor wood-burning fireplace/stove at their longest-lived adult residence and 20.6 % reported annual usage of ≥30 days/year. Compared to those without a wood-burning fireplace/stove, women who used their wood-burning fireplace/stove ≥30 days/year had an elevated rate of lung cancer (HRadj = 1.68; 95 % CI = 1.27, 2.20). In never smokers, positive associations were seen for use 1-29 days/year (HRadj = 1.64; 95 % CI = 0.87, 3.10) and ≥30 days/year (HRadj = 1.99; 95 % CI = 1.02, 3.89). Associations were also elevated across all income groups, in Northeastern, Western or Midwestern U.S. regions, and among those who lived in urban or rural/small town settings. CONCLUSIONS: Our prospective analysis of a cohort of U.S. women found that increasing frequency of wood-burning indoor fireplace/stove usage was associated with incident lung cancer, even among never smokers.