Tobacco smoking poses a major public health challenge around the world and has been estimated to cause 5 million deaths per year globally.¹ Increasing awareness of the harms of cigarette smoking and concerted tobacco control policies (eg, smoking ban laws) have led to substantial decreases in smoking prevalence in the United States and in many other countries.² In addition, the percentage of daily smokers who smoked fewer than 10 cigarettes per day (CPD) increased from 16% to 27% from 2005 to 2014, and the proportion who did not smoke every day increased from 19% to 23%.³ Low-intensity smoking (eg, ≤10 CPD) was traditionally considered a transient smoking reduction practice among individuals who were trying to quit.⁴ However, studies indicate that many low-intensity smokers maintain these smoking patterns for many years over their lifetime.^5,6 Such a smoking pattern has historically been more common among racial and ethnic minorities who nevertheless have high rates of smoking-related morbidity and mortality.^7-9

Previous studies have shown inconsistent associations between red and processed meat intake and breast cancer risk. N‐nitroso compounds and heme iron have been hypothesized as contributing factors. We followed 193,742 postmenopausal women in the NIH‐AARP Diet and Health Study and identified 9,305 incident breast cancers (1995–2006). Dietary intake was assessed using a food frequency questionnaire at baseline. We adjusted daily intakes of meat, nitrite and heme iron for energy intake using the nutrient density method. We estimated multivariable‐adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) by quintiles of dietary exposures for all breast cancer, by stage (in‐situ, localized, regional/distant) and by estrogen/progesterone receptor (ER/PR) status using Cox proportional hazards regression. Total red meat intake was positively associated with risk of regional/distant cancer (p‐trend = 0.02). The risk was 25% higher in the highest vs. lowest intake quintile (95% CI = 1.03–1.52). Higher processed red meat intake (Q5 vs. Q1) was associated with 27% higher risk of localized breast cancer (95% CI = 1.01–1.27, p‐trend = 0.03) and a 19% higher risk of regional/distant cancer (95% CI = 0.98–1.44, p‐trend = 0.10). In addition, higher nitrite intake from processed red meat was positively associated with localized cancer (HR for Q5 vs. Q1 = 1.23, 95% CI = 1.09–1.39, p‐trend < 0.0001). Heme iron intake was positively associated with breast cancer risk overall and all cancer stages (p‐trend = 0.02–0.05). No heterogeneity was observed in risk associations by hormone receptor status. Our findings suggest that high consumption of red meat and processed meat may increase risk of postmenopausal breast cancer. Added nitrite and heme iron may partly contribute to these observed associations.

Tea is one of the most frequently consumed beverages in the United Kingdom and worldwide. Previous studies have suggested a modest mortality benefit associated with tea drinking. This association h... Visual Tea Consumption and Mortality in the UK Biobank. Tea is one of the most frequently consumed beverages in the United Kingdom and worldwide. Previous studies have suggested a modest m... Background: Tea is frequently consumed worldwide, but the association of tea drinking with mortality risk remains inconclusive in populations where black tea is the main type consumed. Objective: T...

Cigarette smoking results in an estimated 480 000 premature deaths in the United States and 7 million deaths worldwide each year.^1,2 In the US, the prevalence of cigarette smoking has decreased dramatically owing to a wide range of public health programs. In 2018, 13.7% of US adults (34.2 million) smoked cigarettes, a 34.4% decrease from 2005 (20.9% [45.1 million adults]).^3,4

Nitrate and nitrite are precursors in the endogenous formation of N‐nitroso compounds (NOC), potential human carcinogens. We evaluated the association of nitrate and nitrite ingestion with postmenopausal ovarian cancer risk in the Iowa Women's Health Study. Among 28,555 postmenopausal women, we identified 315 incident epithelial ovarian cancers from 1986 to 2010. Dietary nitrate and nitrite intakes were assessed at baseline using food frequency questionnaire data. Drinking water source at home was obtained in a 1989 follow‐up survey. Nitrate‐nitrogen (NO₃‐N) and total trihalomethane (TTHM) levels for Iowa public water utilities were linked to residences and average levels were computed based on each woman's duration at the residence. We computed multivariable‐adjusted hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazards regression. We tested interactions of nitrate with TTHMs and dietary factors known to influence NOC formation. Ovarian cancer risk was 2.03 times higher (CI = 1.22–3.38, p_trend = 0.003) in the highest quartile (≥2.98 mg/L) compared with the lowest quartile (≤0.47 mg/L; reference) of NO₃‐N in public water, regardless of TTHM levels. Risk among private well users was also elevated (HR = 1.53, CI = 0.93–2.54) compared with the same reference group. Associations were stronger when vitamin C intake was <median (p_interaction = 0.01 and 0.33 for private well and public supplies, respectively). Dietary nitrate was inversely associated with ovarian cancer risk (p_trend = 0.02); whereas, dietary nitrite from processed meats was positively associated with the risk (p_trend = 0.04). Our findings indicate that high nitrate levels in public drinking water and private well use may increase ovarian cancer risk among postmenopausal women.