Measured adolescent body mass index and adult breast cancer in a cohort of 951,480 women

The Role of Obesity in Breast Cancer Pathogenesis

Research has shown that obesity increases the risk for type 2 diabetes mellitus (Type 2 DM) by promoting insulin resistance, increases serum estrogen levels by the upregulation of aromatase, and promotes the release of reactive oxygen species (ROS) by macrophages. Increased circulating glucose has been shown to activate mammalian target of rapamycin (mTOR), a significant signaling pathway in breast cancer pathogenesis. Estrogen plays an instrumental role in estrogen-receptor-positive breast cancers. The role of ROS in breast cancer warrants continued investigation, in relation to both pathogenesis and treatment of breast cancer. We aim to review the role of obesity in breast cancer pathogenesis and novel therapies mediating obesity-associated breast cancer development. We explore the association between body mass index (BMI) and breast cancer incidence and the mechanisms by which oxidative stress modulates breast cancer pathogenesis. We discuss the role of glutathione, a ubiquitous antioxidant, in breast cancer therapy. Lastly, we review breast cancer therapies targeting mTOR signaling, leptin signaling, blood sugar reduction, and novel immunotherapy targets.

Association of childhood and adolescence obesity with incidence and mortality of adulthood cancers. A systematic review and meta-analysis

BACKGROUND

Prevalence and subsequent conditions of childhood and adolescent obesity are increasing. It has been seen that obesity in youth is associated with adulthood cancer. This systematic review and meta-analysis aimed to determine the pooled association of childhood obesity with cancers in adulthood.

METHODS

In this systematic review, international electronic databases such as Scopus, PubMed, Web of Science, and EMBASE were searched using relevant keywords until February 2022. All Cohort studies assessing the association of childhood and adolescent obesity (under 18 years old) with the incidence and mortality of all types of cancers were included. Two independent reviewers screened and carried out the quality assessment of included studies. Between-studies heterogeneity was assessed using the I squared and Cochran's Q tests. Random/fixed-effect meta-analyses were used to pool the appropriate effect sizes (Hazard ratios (HR)).

RESULTS

Overall, 46 studies were found to be relevant and were included in this study. Based on the random-effects model meta-analysis, childhood obesity increased the hazard of cancer incidence and mortality in adulthood by 33% (HR: 1.33, 95%CI (1.25, 1.41)) and by 28% (HR: 1.28, 95%CI (1.13, 1.42)), respectively. In the subgroups meta-analysis, the HR of childhood obesity and adulthood cancer incidence mortality in women was higher than in men (HR=1.39, 95%CI (1.25, 1.53) vs HR= 1.20, 95%CI (1.07, 1.32)) and (HR= 1.40, 95%CI (1.10, 1.69) vs HR=1.20, 95%CI (1.04, 1.36)) respectively.

CONCLUSION

This study found that obesity in childhood and adolescence is associated with a significant increase in the incidence and mortality of cancers in adulthood. Prevention of childhood obesity, in addition to its short-term beneficial effects, can reduce the burden of cancer in adulthood. The data sets of this study are present in the Tables of the current manuscript. Moreover this study was registered online in PROSPERO (registration code: CRD42022331958).

SYSTEMIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/Prospero/, identifier CRD42022331958.

Early-life body mass index and risks of breast, endometrial, and ovarian cancers: a dose-response meta-analysis of prospective studies

BACKGROUND

The evidence for the associations between early-life adiposity and female cancer risks is mixed. Little is known about the exact shape of the relationships and whether the associations are independent of adult adiposity.

METHODS

We conducted dose-response meta-analyses of prospective studies to summarise the relationships of early-life body mass index (BMI) with breast, endometrial, and ovarian cancer risks. Pubmed and Embase were searched through June 2020 to identify relevant studies. Using random-effects models, the summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated per 5-kg/m² increase in BMI at ages ≤ 25 years. A nonlinear dose-response meta-analysis was conducted using restricted cubic spline analysis.

RESULTS

After screening 33,948 publications, 37 prospective studies were included in this analysis. The summary RRs associated with every 5-kg/m² increase in early-life BMI were 0.84 (95% CI = 0.81-0.87) for breast, 1.40 (95% CI = 1.25-1.57) for endometrial, and 1.15 (95% CI = 1.07-1.23) for ovarian cancers. For breast cancer, the association remained statistically significant after adjustment for adult BMI (RR = 0.80, 95% CI = 0.73-0.87). For premenopausal breast, endometrial, and ovarian cancers, the dose-response curves suggested evidence of nonlinearity.

CONCLUSIONS

With early-life adiposity, our data support an inverse association with breast cancer and positive associations with ovarian and endometrial cancer risks.

Adolescent and Childhood Obesity and Excess Morbidity and Mortality in Young Adulthood-a Systematic Review

PURPOSE OF REVIEW

Rates of childhood obesity have been soaring in recent decades. The association between obesity in adulthood and excess morbidity and mortality has been readily established, whereas the association of childhood and adolescent obesity has not. The purpose of this review is to summarize existing data regarding the association of the presence of obesity in childhood/adolescence and early-onset adverse outcomes in adulthood, with specific focus on young adults under the age of 45 years.

RECENT FINDINGS

Diabetes, cancer, and cardiometabolic outcomes in midlife are closely linked to childhood and adolescent obesity. Childhood and adolescent obesity confer major risks of excess and premature morbidity and mortality, which may be evident before age 30 years in both sexes. The scientific literature is mixed regarding the independent risk of illness, which may be attributed to childhood BMI regardless of adult BMI, and additional data is required to establish causality between the two. Nonetheless, the increasing prevalence of childhood and adolescent obesity may impose an increase of disease burden in midlife, emphasizing the need for effective interventions to be implemented at a young age.

Photovoice-Based Assessment of Weight Management Experiences of Breast Cancer Patients Treated with Tamoxifen

In this study, an in-depth analysis of weight management experiences of breast cancer patients treated with tamoxifen is conducted, thereby providing basic data to help develop a multidimensional strategy to reduce recurrence and increase the survival rate of breast cancer patients. Study participants included nine breast cancer patients who were treated with tamoxifen at Kosin University Hospital and Saegyero Hospital in Busan Metropolitan City, Korea. This study employed the photovoice methodology. Participants described the need for family support and cooperation with weight management, provision of personalized weight management programs by medical institutions, provision of information on weight management programs by the community, and financial support for the weight management programs for breast cancer patients at the national level. This study emphasized the importance of weight management for breast cancer patients treated with tamoxifen and collected and analyzed vivid opinions of these patients using photos taken by them.

Adolescent overweight and obesity and the risk of papillary thyroid cancer in adulthood: a large-scale case-control study

This study aimed to investigate the association between adolescent overweight and obesity and PTC risk in adulthood. We conducted a case-control study in the Republic of Korea with 1,549 PTC patients and 15,490 controls individually matched for age and sex. We estimated body mass index (BMI) at age 18 years from self-reported weight at this age. Compared with BMI < 23.0 at age 18 years, BMI ≥ 25.0 at age 18 years was associated with higher PTC risk (odds ratio [OR] = 4.31, 95% confidence interval [CI]: 3.57, 5.22). The association between BMI ≥ 25.0 at age 18 years and PTC risk was stronger among men (OR = 6.65, 95% CI: 4.78, 9.27) than among women (OR = 3.49, 95% CI: 2.74, 4.43), and stronger among individuals with current BMI ≥ 25.0 (OR = 8.21, 95% CI: 6.34, 10.62) than among those with current BMI < 25.0 (OR = 2.21, 95% CI: 1.49, 3.27). Among PTC patients, BMI ≥ 25.0 at age 18 years was associated with extra-thyroidal extension and T stage ≥2, but not with N stage ≥1 or BRAFV600E mutation. Adolescent overweight and obesity was associated with higher risk of PTC in adulthood. Our results emphasise the importance of weight management in adolescence to decrease the PTC risk.

Risk factors for estrogen receptor positive ductal carcinoma in situ of the breast in African American women

Background

Compared to U.S. white women, African American women are more likely to die from ductal carcinoma in situ (DCIS). Elucidation of risk factors for DCIS in African American women may provide opportunities for risk reduction.

Methods

We used data from three epidemiologic studies in the African American Breast Cancer Epidemiology and Risk Consortium to study risk factors for estrogen receptor (ER) positive DCIS (488 cases; 13,830 controls). Results were compared to associations observed for ER+ invasive breast cancer (n = 2,099).

Results

First degree family history of breast cancer was associated with increased risk of ER+ DCIS [odds ratio (OR): 1.69, 95% confidence interval (CI): 1.31, 2.17]. Oral contraceptive use within the past 10 years (vs. never) was also associated with increased risk (OR: 1.43, 95%CI: 1.03, 1.97), as was late age at first birth (≥25 years vs. <20 years) (OR: 1.26, 95%CI: 0.96, 1.67). Risk was reduced in women with older age at menarche (≥15 years vs. <11 years) (OR: 0.62, 95%CI: 0.42, 0.93) and higher body mass index (BMI) in early adulthood (≥25 vs. <20 kg/m² at age 18 or 21) (OR: 0.75, 95%CI: 0.55, 1.01). There was a positive association of recent BMI with risk in postmenopausal women only. In general, associations of risk factors for ER+ DCIS were similar in magnitude and direction to those for invasive ER+ breast cancer.

Conclusions

Our findings suggest that most risk factors for invasive ER+ breast cancer are also associated with increased risk of ER+ DCIS among African American women.

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Few studies of risk factors for ductal carcinoma in situ (DCIS) have evaluated associations for African American women.

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We analyzed data from the African American African American Breast Cancer Epidemiology and Risk (AMBER) Consortium.

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Family history of breast cancer, reproductive factors, and anthropometric factors were associated with risk of ER+ DCIS.

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In general, risk factor associations for ER+ DCIS were similar to those for ER+ invasive breast cancer.

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Our findings support a common etiology and pathogenesis between ER+ DICS and ER+ invasive cancer in African American women.

Metabolic Health, Insulin, and Breast Cancer: Why Oncologists Should Care About Insulin

Studies investigating the potential link between adult pre-menopausal obesity [as measured by body mass index (BMI)] and triple-negative breast cancer have been inconsistent. Recent studies show that BMI is not an exact measure of metabolic health; individuals can be obese (BMI > 30 kg/m²) and metabolically healthy or lean (BMI < 25 kg/m²) and metabolically unhealthy. Consequently, there is a need to better understand the molecular signaling pathways that might be activated in individuals that are metabolically unhealthy and how these signaling pathways may drive biologically aggressive breast cancer. One key driver of both type-2 diabetes and cancer is insulin. Insulin is a potent hormone that activates many pathways that drive aggressive breast cancer biology. Here, we review (1) the controversial relationship between obesity and breast cancer, (2) the impact of insulin on organs, subcellular components, and cancer processes, (3) the potential link between insulin-signaling and cancer, and (4) consider time points during breast cancer prevention and treatment where insulin-signaling could be better controlled, with the ultimate goal of improving overall health, optimizing breast cancer prevention, and improving breast cancer survival.

Prevalence of breast cancer-related risk factors in underweight premenopausal women: the Korea National Health and Nutrition Examination Survey IV-VI

PURPOSE

This study aimed to examine the prevalence and trends of breast cancer-related risk factors and characteristics in premenopausal underweight Korean women according to birth year cohort.

METHODS

Socioeconomic and breast cancer-related risk factors were investigated in 13,415 premenopausal women using nationwide cross-sectional surveys performed between 2007 and 2015. Underweight was defined as body mass index < 18.5 kg/m². Multivariable models were created using complex sample procedures.

RESULTS

Underweight women comprised 9.5% of the sample. Compared with those who were obese or of normal weight, underweight women were characterized by younger age, higher rate of metropolitan residence, higher economic status, more education, higher rates of non-manual employment and unmarried status, lower rate of early menarche, higher rates of nulliparity, lower parity, alcohol consumption, and never having breastfed, and lower levels of high physical activity. Multivariable analysis showed that underweight women had a significantly lower rate of early menarche, lower parity, higher nulliparity, older age at first delivery, and lower levels of high physical activity compared to premenopausal women with normal weight. These trends were more apparent among women born in recent years.

CONCLUSIONS

Underweight Korean premenopausal women exhibit distinctive features associated with an increased risk of breast cancer, except for a lower rate of early menarche. These associations were prominent in recent generations. Assessment of the association between underweight and premenopausal breast cancer risk should focus on promoting healthy lifestyles to reduce breast cancer risk.

Association of Body Mass Index and Age With Subsequent Breast Cancer Risk in Premenopausal Women

Importance

The association between increasing body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) and risk of breast cancer is unique in cancer epidemiology in that a crossover effect exists, with risk reduction before and risk increase after menopause. The inverse association with premenopausal breast cancer risk is poorly characterized but might be important in the understanding of breast cancer causation.

Objective

To investigate the association of BMI with premenopausal breast cancer risk, in particular by age at BMI, attained age, risk factors for breast cancer, and tumor characteristics.

Design, Setting, and Participants

This multicenter analysis used pooled individual-level data from 758 592 premenopausal women from 19 prospective cohorts to estimate hazard ratios (HRs) of premenopausal breast cancer in association with BMI from ages 18 through 54 years using Cox proportional hazards regression analysis. Median follow-up was 9.3 years (interquartile range, 4.9-13.5 years) per participant, with 13 082 incident cases of breast cancer. Participants were recruited from January 1, 1963, through December 31, 2013, and data were analyzed from September 1, 2013, through December 31, 2017.

Exposures

Body mass index at ages 18 to 24, 25 to 34, 35 to 44, and 45 to 54 years.

Main Outcomes and Measures

Invasive or in situ premenopausal breast cancer.

Results

Among the 758 592 premenopausal women (median age, 40.6 years; interquartile range, 35.2-45.5 years) included in the analysis, inverse linear associations of BMI with breast cancer risk were found that were stronger for BMI at ages 18 to 24 years (HR per 5 kg/m2 [5.0-U] difference, 0.77; 95% CI, 0.73-0.80) than for BMI at ages 45 to 54 years (HR per 5.0-U difference, 0.88; 95% CI, 0.86-0.91). The inverse associations were observed even among nonoverweight women. There was a 4.2-fold risk gradient between the highest and lowest BMI categories (BMI≥35.0 vs <17.0) at ages 18 to 24 years (HR, 0.24; 95% CI, 0.14-0.40). Hazard ratios did not appreciably vary by attained age or between strata of other breast cancer risk factors. Associations were stronger for estrogen receptor-positive and/or progesterone receptor-positive than for hormone receptor-negative breast cancer for BMI at every age group (eg, for BMI at age 18 to 24 years: HR per 5.0-U difference for estrogen receptor-positive and progesterone receptor-positive tumors, 0.76 [95% CI, 0.70-0.81] vs hormone receptor-negative tumors, 0.85 [95% CI: 0.76-0.95]); BMI at ages 25 to 54 years was not consistently associated with triple-negative or hormone receptor-negative breast cancer overall.

Conclusions and Relevance

The results of this study suggest that increased adiposity is associated with a reduced risk of premenopausal breast cancer at a greater magnitude than previously shown and across the entire distribution of BMI. The strongest associations of risk were observed for BMI in early adulthood. Understanding the biological mechanisms underlying these associations could have important preventive potential.

Body fatness at a young age, body fatness gain and risk of breast cancer: systematic review and meta-analysis of cohort studies

Higher body fatness in adulthood has been consistently associated with an increased risk of postmenopausal breast cancer, as well as a tendency towards a lower risk of premenopausal breast cancer. However, the association between body fatness at a young age (≤30 years), body fatness gain and the risk of breast cancer is less defined. PubMed and Web of Science databases were searched to identify relevant publications. Risk estimates with 95% confidence intervals from each study were transformed into a continuous variable for each 5 kg m^-2 increase in body mass index (BMI) and were pooled under a random-effects model. Each 5 kg m^-2 increase in BMI was significantly associated with a 14%, 12% and 17% lower risk of breast cancer later in life among all women, premenopausal women and postmenopausal women, respectively. Significant heterogeneity and publication bias were observed. The results remained unchanged after the trim and fill method was applied to correct the bias. Each 5 kg m^-2 increase in BMI from a young age until cohort entry was significantly associated with a 13% and 14% higher risk of breast cancer in all women and postmenopausal women, respectively. In summary, higher body fatness at a young age may have a protective role in the later development of breast cancer in both premenopausal and postmenopausal women. However, this potential benefit should not be overemphasized, as our findings suggest that increased body fatness gain from a young age is positively associated with postmenopausal breast cancer risk. These findings further justify the need to maintain a steady weight throughout life.

Adolescent Body Mass Index and Cardiovascular Disease-Specific Mortality by Midlife

CONTEXT

As opposed to coronary heart disease (CHD) mortality, cardiovascular mortality attributed to non-CHD causes has increased.

OBJECTIVE

To evaluate the association of body mass index (BMI) in late adolescence with mortality attributed to non-CHD cardiovascular sequelae.

DESIGN AND SETTING

A nationwide cohort.

PARTICIPANTS

A total of 2,294,139 adolescents examined between 1967 and 2010.

INTERVENTIONS

Height and weight were measured at age 17. All cardiovascular disease-specific outcomes, coded by the Central Bureau of Statistics from death notifications as the underlying cause of death, were obtained by linkage. Cox hazards models were applied.

MAIN OUTCOME MEASUREMENTS

Death attributed to fatal arrhythmias, hypertensive heart disease, cardiomyopathies, arterial disease, heart failure, and pulmonary embolism.

RESULTS

During 42,297,007 person-years of follow-up, there were 3178 deaths due to cardiovascular causes, of which 279, 122, 121, 114, 94, and 70 were attributed to the main outcomes, respectively. BMI was positively associated with all study outcomes with hazard ratios (HRs) per unit increment in BMI ranging from 1.09 [95% confidence interval (CI): 1.03 to 1.16] for arterial disease to 1.16 (95% CI: 1.11 to 1.21) for hypertensive heart disease. When BMI was treated as a categorical variable, a graded increase in risk was evident from the high-normal (22.0 to <25.0 kg/m2) to the overweight to the obese categories, with HRs of 1.4, 1.7, and 3.7 for arrhythmias; 1.9, 4.1, and 8.0 for hypertensive heart disease; 1.5, 2.4, and 4.0 for cardiomyopathies, 2.7, 5.0, and 3.5; for arterial disease, 1.7, 2.7, and 5.4 for heart failure; and 1.3, 1.8, and 3.0 for pulmonary embolism. Findings persisted in extensive sensitivity analyses.

CONCLUSIONS

Adolescent BMI within the accepted normal range is associated with non-CHD nonstroke cardiovascular outcomes.

Higher body mass index in 16-19 year-old Jewish Adolescents of North African, Middle Eastern and European Origins is a Predictor of Acute Myeloid Leukemia: a cohort of 2.3 million Israelis

PURPOSE

Studies evaluating adolescent risk factors for developing acute myeloid leukemia (AML) are virtually nonexistent. We assessed adolescent predictors of AML in adults, with a main focus on adolescent BMI.

METHODS

The study included 2,310,922 16-19-year-old Jewish Israeli adolescents (mean age 17.3 ± 0.4, 59.5% male), called up for an obligatory health examination. Sociodemographic and health data, including measured weight and height, were gathered. Body mass index (BMI) was examined both as a continuous variable and grouped according to the World Health Organization (WHO) classification and US-CDC percentiles. Bone-marrow-biopsy-verified AML cases diagnosed up to 31 December 2012 were identified by linkage to the Israel national cancer registry. Multivariable-adjusted Cox proportional-hazards models were used to model time to diagnosis.

RESULTS

During 47 million person years of follow-up, 568 AML cases were identified (crude incidence rate 1.21/100,000 person years). There was a multivariable-adjusted hazard ratio (HR) of 1.041 (95% CI 1.015-1.068, p = 0.002) per unit BMI. The association was evident in those of Middle Eastern, North African, and European origin. A graded association was evident across the overweight and obese WHO grouping. With the US-CDC grouping, excess risk was evident in overweight but not in obese adolescents, although a test for trend in percentiles was significant (p = 0.004). Borderline associations were noted for origin (p = 0.065) (higher in the predominantly Ashkenazi European origin), sex (higher in women: HR = 1.24 (95% CI 0.99-1.55), and stature (HR = 1.013, 95% CI 1.000-1.026, per cm).

CONCLUSIONS

Higher BMI in adolescence was associated with increased AML incidence in adulthood in this multiethnic population.