Birth cohort differences in reproductive and lifestyle breast cancer risk factors among women in the Nigerian breast cancer study

Reproductive Risk Factors and Their Association with Breast Cancer in Women of Central India

Several reproductive factors are significantly associated with breast cancer risk among women in Central India and promotion of breastfeeding and identification of women with adverse reproductive profiles may facilitate early screening and risk reduction strategies.

Association between smoking habits and breast density, changes in breast density, and breast cancer in Asian women.

Adiposity and risk of breast cancer in 280 000 Chinese women: a prospective cohort study

Abstract Background Adiposity is associated with increased risk of breast cancer in post-menopausal women, while the association appears to be the inverse among premenopausal women in Western populations, but is unclear for Chinese women. Methods Using data on 284 538 women with no history of cancer, hysterectomy, oophorectomy, or breast surgery at baseline in 2004–8 from the China Kadoorie Biobank (a prospective cohort study), Cox regression was used to estimate adjusted hazard ratios (HRs) for breast cancer and its subtypes by measured body mass index (BMI) and other adiposity measures (waist circumference, fat percentage, waist–hip ratio, fat mass) and by self-reported BMI at age 25 years. Results Mean BMI was 23.8 (3.5 SD) kg/m2 at baseline (mean age 51.4 years) and 21.9 (2.7 SD) kg/m2 at age 25 years. During 10 years of follow-up, there were 2379 incident breast cancer cases. Higher BMI was associated with a higher risk of breast cancer in women who were post-menopausal [HR = 1.35, 95% confidence interval (CI) 1.24–1.47] and premenopausal (HR = 1.13, 95% CI 1.03–1.24) at baseline, but not when censoring at age 50 years to capture mainly premenopausal cancers. Among post-menopausal women, BMI was associated with oestrogen-receptor positive (ER ) (HR = 1.47, 95% CI 1.24–1.74), but not with oestrogen-receptor negative (ER−) breast cancer (HR = 1.02, 95% CI 0.75–1.37). Waist circumference and fat percentage were associated with a higher risk of breast cancer. Conclusion In this cohort of Chinese women, higher levels of general and central adiposity were associated with a higher risk of breast cancer, in both women who were premenopausal and women who were post-menopausal at baseline. Among post-menopausal women, adiposity was associated with ER   but not ER − breast cancer.

Risk factors associated with molecular subtypes of breast cancer among indian women: a multicentre matched case-control study.

Impact of lifestyle, familial history and environmental factors on breast cancer development among 80 women in Calabar Nigeria

The results of the study indicated that lifestyle, environmental, and familial history factors did not have a significant impact on the development of breast cancer among the participants, as the associated probability values were greater than the level of significance for all the three factors.

Global patterns, temporal trends and socioeconomic inequalities in the burden of breast cancer: a population-based study across 185 countries

Objective: Breast cancer is the most frequently diagnosed cancer among women worldwide and is a leading cause of cancer-related deaths. Comparative assessments of breast cancer lifetime risks across populations are limited. This study estimated the global, regional, and national lifetime risks, temporal trends, and socioeconomic inequalities in the burden of breast cancer. Methods: Using incidence and mortality data from GLOBOCAN 2022 (185 countries) and United Nations population and all-cause death data, lifetime risks were calculated using the adjusted for multiple primaries (AMP) method, which could adjust for multiple primary cancers, competing risks of other causes death, and life expectancy. Longitudinal data of breast cancer incidence from 2003–2017 were retrieved from the Cancer Incidence in Five Continents (CI5) Plus database. The temporal trends for breast cancer deaths were abstracted from the WHO Mortality Database. The lifetime risk of developing and dying from breast cancer were analyzed by socioeconomic characteristics, 20 predefined geographic regions and menopausal status. Results: The overall worldwide lifetime risk of developing and dying from breast cancer was 5.51% (95% CI: 5.50%–5.52%) and 1.82% (95% CI: 1.82%–1.83%) in 2022, respectively. The estimated lifetime risks of developing breast cancer had a positive relationship with Human Development Index (HDI) levels and corresponding risks of 10.37%, 4.42%, 2.96%, and 2.91% in very high, high, middle, and low HDI regions, respectively. Very high HDI regions presented the highest lifetime risk of breast cancer death (2.70%), followed by low HDI (1.70%), medium HDI (1.54%), and high (1.38%) HDI regions. A significant correlation was identified between lifetime risks and health economics capacity. The lifetime risk of developing and dying from breast cancer primarily involved individuals ≥ 55 years of age with remaining risks of 3.77% (developing) and 1.43% (dying) from 55 years to death. The proportion of lifetime risks among individuals 0–44 years of age was higher in Africa regions compared to other regions. In surveillance data from 36 countries, a significant increasing trend in the average annual percentage change (AAPC) was noted in 32 countries, which ranged from 0.17% in the United States to 5.84% in the Republic of Korea. Conclusions: Globally, an estimated 1 in 18 individuals were diagnosed with breast cancer during their lifetime and approximately 1 in 55 died from the disease in 2022. Lifetime risk of breast cancer disparities reveal the socioeconomic inequalities of breast cancer. Therefore, country-tailored intervention plans for breast cancer require prioritization within precision prevention to mitigate global breast cancer inequities and burden.