Sedentary work and breast cancer risk: A systematic review and meta-analysis

Is work burden associated with postmenopausal breast cancer? A population-based 25-year follow-up

OBJECTIVE

To study the association between breast cancer and work burden over 25 years.

METHODS

The study was based on the Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) cohort (n = 14,220) and included women who had answered the questionnaire from the year 1994 and had no previous breast cancer. Breast cancer cases were recorded from the Finnish Cancer Registry during the study period: from 1st June 1994 till December 31, 2019. Using questionnaires, we collected information on work burden, body mass index (BMI), menopausal hormone therapy (MHT), alcohol consumption, parity, and family history of breast cancer. Work burden was categorized as low or high. Variables were used both in the univariate and multivariate Cox regression analyses to explore their associations with breast cancer.

RESULTS

Altogether 825 women (6.9%) were diagnosed with breast cancer during the study period with a mean follow-up of 13.3 ± 7.2 years. Women with breast cancer were compared to those without breast cancer during the follow-up period (n = 11,117). A low work burden was associated with a 1.3-fold higher incidence of breast cancer (95% confidence interval 1.2-1.6) than a high work burden. Low work burden was associated with an increased breast cancer risk.

CONCLUSION

Low work burden is associated with elevated postmenopausal breast cancer risk in the 25-year follow-up period.

Synchronous or metachronous breast and colorectal cancers in younger-than-average-age patients: a case series

BACKGROUND

The incidence of breast and colorectal cancer (CRC) in younger-than-average-age patients is rising and poorly understood. This is the largest study on patients with both cancers who are less than 60 years old and aims to characterize demographic, clinicopathologic, and genetic features and describe therapeutic dilemmas and management strategies.

MATERIALS AND METHODS

This is a retrospective medical records review of patients at the University of California San Francisco with both primary breast and CRC before age 60.

RESULTS

Fifty-one patients were identified; 41 had detailed medical records. Median age of diagnosis with breast cancer was 43 (range 27-59) and CRC was 50 (28-59). Most were Caucasian (38, 74.5%) and never smokers (23, 56.1%); about half were current alcohol consumers (20, 48.8%) and about one-third had sedentary jobs (14, 34.1%). Average BMI was 25.8 (range: 14-49), and 30% were overweight or obese. Breast was the first cancer diagnosed in 36 patients (70.6%) and 44 (86.3%) had a metachronous CRC diagnosis. Breast cancer was early stage (0-2) in 32 (78.0%) patients whereas CRC was split between early stage (1-2) in 14 (34.1%) and later stage (3-4) in 19 (46.2%). Ten patients (24.3%) had a known germline mutation, although 23 (56.1%) had a family history of cancer in a first-degree relative.

CONCLUSION

Younger patients with both breast and CRC are a unique cohort, often without known risk factors. Alcohol consumption and sedentary jobs were the most common risk factors, and about one-quarter had a known genetic predisposition. Comanagement of both cancers requires individualized, multidisciplinary care.

Epidemiological breast cancer prediction by country: A novel machine learning approach

Breast cancer remains a significant contributor to cancer-related deaths among women globally. We seek for this study to examine the correlation between the incidence rates of breast cancer and newly identified risk factors. Additionally, we aim to utilize machine learning models to predict breast cancer incidence at a country level. Following an extensive review of the available literature, we have identified a range of recently studied risk factors associated with breast cancer. Subsequently, we gathered data on these factors and breast cancer incidence rates from numerous online sources encompassing 151 countries. To evaluate the relationship between these factors and breast cancer incidence, we assessed the normality of the data and conducted Spearman's correlation test. Furthermore, we refined six regression models to forecast future breast cancer incidence rates. Our findings indicate that the incidence of breast cancer is most positively correlated with the average age of women in a country, as well as factors such as meat consumption, CO2 emissions, depression, sugar consumption, tobacco use, milk intake, mobile cells, alcohol consumption, pesticides, and oral contraceptive use. As for prediction, the CatBoost Regressor successfully predicted future breast cancer incidence with an R squared value of 0.84 ± 0.03. An increased incidence of breast cancer is mainly associated with dietary habits and lifestyle. Our findings and recommendations can serve as a baseline for developing educational programs intended to heighten awareness amongst women in countries with heightened risk.

Non-genetic factors and breast cancer: an umbrella review of meta-analyses

BACKGROUND

Previous research has found associations between various non-genetic factors and breast cancer (BrCa) risk. This study summarises and appraises the credibility of the available evidence on the association between non-genetic factors and BrCa risk.

METHODS

We conducted an umbrella review of meta-analyses. Medline, Scopus, and the Cochrane databases were systematically searched for meta-analyses examining non-genetic factors and BrCa incidence or mortality. The strength of the evidence was graded in four categories (i.e., weak, suggestive, highly suggestive, convincing).

RESULTS

A total of 781 meta-analyses from 280 publications were evaluated and graded. We included exposures related to anthropometric measurements, biomarkers, breast characteristics and diseases, diet and supplements, environment, exogenous hormones, lifestyle and social factors, medical history, medication, reproductive history, and pregnancy. The largest number of examined associations was found for the category of diet and supplements and for exposures such as aspirin use and active smoking. The statistically significant (P-value < 0.05) meta-analyses were 382 (49%), of which 204 (53.4%) reported factors associated with increased BrCa risk. Most of the statistically significant evidence (n = 224, 58.6%) was graded as weak. Convincing harmful associations with heightened BrCa risk were found for increased body mass index (BMI), BMI and weight gain in postmenopausal women, oral contraceptive use in premenopausal women, increased androstenedione, estradiol, estrone, and testosterone concentrations, high Breast Imaging Reporting and Data System (BIRADS) classification, and increased breast density. Convincing protective factors associated with lower BrCa risk included high fiber intake and high sex hormone binding globulin (SHBG) levels while highly suggestive protective factors included high 25 hydroxy vitamin D [25(OH)D] levels, adherence to healthy lifestyle, and moderate-vigorous physical activity.

CONCLUSIONS

Our findings suggest some highly modifiable factors that protect from BrCa. Interestingly, while diet was the most studied exposure category, the related associations failed to reach higher levels of evidence, indicating the methodological limitations in the field. To improve the validity of these associations, future research should utilise more robust study designs and better exposure assessment techniques. Overall, our study provides knowledge that supports the development of evidence-based BrCa prevention recommendations and guidance, both at an individual level and for public health initiatives.

TRIAL REGISTRATION

PROSPERO CRD42022370675.

Interaction of sedentary behaviour and educational level in breast cancer risk

OBJECTIVE

This cross-sectional study aims to analyse the relationship between sedentary behaviour and breast cancer (BC) risk from a social perspective.

METHODS

Women aged 45-70 who participated in the Valencia Region Breast Cancer Screening Programme (2018-2019) were included, with a total of 121,359 women analysed, including 506 with cancer and 120,853 without cancer. The response variable was BC (screen-detected) and the main explanatory variable was sedentary behaviour (≤2 / >2-≤3 / >3-≤5 / >5 hours/day, h/d). Nested logistic regression models (M) were estimated: M1: sedentary behaviour adjusted for age and family history of BC; M2: M1 + hormonal/reproductive variables (menopausal status, number of pregnancies, hormone replacement therapy; in addition, months of breastfeeding was added for a subsample of women with one or more live births); M3: M2 + lifestyle variables (body mass index, smoking habits); M4: M3 + socioeconomic variables (educational level, occupation); Final model: M4 + gender variables (childcare responsibilities, family size). Interaction between sedentary behaviour and educational level was analysed in the Final model. Moreover, for the whole sample, postmenopausal women and HR+ BC, the Final model was stratified by educational level.

RESULTS

Sedentary behaviour was associated with an increased risk of BC with a nearly statistically significant effect in the Final model (>2-≤3 h/d: OR = 1.22 (0.93-1.61); >3-≤5 h/d: OR = 1.14 (0.86-1.52); >5: OR = 1.19 (0.89-1.60)). For women with a low educational level, sitting more than 2 h/d was associated with an increased risk of BC in the whole sample (>2-≤3 h/d OR = 1.93 (1.19-3.21); in postmenopausal women (>2-≤3 h/d, OR = 2.12 (1.18-2.96), >5h/d OR = 1.75 (1.01-3.11)) and in HR+ BC (>2-≤3h/d, OR = 2.15 (1.22-3.99)). Similar results were observed for women with one or more live births. Conclusions Sitting >2 h/d is associated with BC risk in women with low educational level, especially in postmenopausal women and those with live births.

Joint associations of sedentary behavior and domain-specific physical activity on C-reactive protein in Korea

Sedentary behavior (SB) and physical activity (PA) exert opposing effects on inflammatory markers. This study examined the associations of a more subdivided combination of PA and SB with high-sensitivity C-reactive protein (hs-CRP). Using the 2014-2019 Korean National Health and Nutrition Examination Survey, this cross-sectional study analyzed 20,541 adults. The independent variables were SB, defined as ≥10 h of sitting per day, and three domains of PA: occupational PA (OPA) during work, leisure-time PA (LPA) during leisure time, and transportation PA (TPA) or active commuting. The dependent variable was hs-CRP ≥ 1.0 mg/L. Besides exploring the individual association of SB and each PA with hs-CRP, the combined association of SB and each PA with hs-CRP was also examined using multiple logistic regression. The analyses indicated that concurrent exposure to SB and OPA (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.02-1.80) significantly raised the likelihood of increased hs-CRP, while SB without LPA (OR 1.26, 95% CI 1.11-1.41) or TPA (OR 1.19, 95% CI 1.08-1.31) significantly increased risk of higher hs-CRP, compared to their respective reference. The absence of non-occupational PA such as LPA or TPA combined with SB was associated with the increased hs-CRP risk, whereas OPA increased the risk when present concurrently with SB. Reducing SB and OPA while increasing LPA and TPA, is necessary to reduce inflammatory conditions.

Physical Activity, Sedentary Time, and Psychosocial Functioning among Adults with Cancer: A Scoping Review

The post-treatment period (after the completion of primary cancer treatment) is a phase during which adults with cancer are particularly vulnerable to the physical and psychological side effects of treatment. Adopting healthy lifestyle habits during this time is essential to mitigate these effects. This scoping review investigated the associations of physical activity (PA) and sedentary time (ST) with two post-treatment psychosocial indicators among adults with cancer: psychological functioning and quality of life (QoL). An exhaustive search was performed in January 2023 across five databases, namely APA PsycInfo, MedLine, SPORTDiscuss, SCOPUS, and CINAHL, adhering to PRISMA guidelines for scoping reviews. Twenty articles met the inclusion criteria; 16 used a cross-sectional design, while 4 used a longitudinal one. PA and ST were assessed mainly with accelerometers (n = 17), and psychosocial indicators with self-reported questionnaires (n = 20). Most studies linked higher PA levels to reduced anxiety (n = 3) and depression (n = 4) symptoms, and elevated ST to higher psychological symptoms (n = 3). Opposite associations were observed for QoL (n = 5). Altogether, PA appeared to be more strongly related to psychological functioning and QoL than ST. This scoping review highlights associations of PA and ST with psychological functioning and QoL among adults with cancer in the post-treatment period. However, future studies must prioritize longitudinal designs to establish directionality.

Seven-plus hours of daily sedentary time and the subsequent risk of breast cancer: Japan Multi-Institutional Collaborative Cohort Study

This study aimed to investigate the association between daily sedentary time and the risk of breast cancer (BC) in a large Japanese population. The participants were 36,023 women aged 35-69 years from the Japan Multi-Institutional Collaborative Cohort Study. Cox proportional hazards analysis was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for BC incidence in relation to time spent sedentarily (categorical variables: <7 and ≥7 hours/day [h/d]). Additionally, the associations of BC incidence to the joint effect of sedentary time with each component of physical activity, such as leisure-time metabolic equivalents (METs), frequency of leisure-time physical activity, and daily walking time, were examined. During 315,189 person-years of follow-up, 554 incident cases of BC were identified. When compared to participants who spent <7 h/d sedentary, those who spent ≥7 h/d sedentary have a significantly higher risk of BC (HR, 1.36; 95% CI, 1.07-1.71). The corresponding HRs among participants who spent ≥7 h/d sedentary with more physical activity, such as ≥1 h/d for leisure-time METs, ≥3 days/week of leisure-time physical activity, and ≥1 h/d of daily walking were 1.58 (95% CI, 1.11-2.25), 1.77 (95% CI, 1.20-2.61), and 1.42 (95% CI, 1.10-1.83), respectively, compared with those who spent <7 h/d sedentary. This study found that spending ≥7 h/d of sedentary time is associated with the risk of BC. Neither leisure-time physical activity nor walking had a BC-preventive effect in those with ≥7 h/d of sedentary time.

Effect of genetic liability to migraine and its subtypes on breast cancer: a mendelian randomization study

BACKGROUND

The relationship between migraine and breast cancer risk has generated conflicting findings. We attempted to assess the association between migraine and breast cancer risk using Mendelian randomization (MR) analysis.

METHODS

We selected genetic instruments associated with migraine from a recently published genome-wide association studies (GWAS). Inverse variant weighted (IVW) analysis was adopted as the main method, and we also performed the weighted-median method and the MR‒Egger, MR pleiotropy residual sum and outlier (MR-PRESSO), and MR Robust Adjusted Profile Score (MR-RAPS) methods as supplements.

RESULTS

Our MR suggested that any migraine (AM) was a risk factor for overall breast cancer (IVW: odds ratio (OR) = 1.072, 95% confidence intervals (CI) = 1.035-1.110, P = 8.78 × 10- 5, false discovery rate (FDR) = 7.36 × 10- 4) and estrogen receptor-positive (ER+) breast cancer (IVW: OR = 1.066, 95% CI = 1.023-1.111, P = 0.0024; FDR = 0.0108) but not estrogen receptor-negative (ER-) breast cancer. In its subtype analysis, women with a history of migraine without aura (MO) had an increased risk of ER- breast cancer (IVW: OR = 1.089, 95% CI = 1.019-1.163, P = 0.0118, FDR = 0.0354), and MO was suggestively associated with the risk of overall breast cancer (FDR > 0.05 and IVW P < 0.05). No significant heterogeneity or horizontal pleiotropy was found in the sensitivity analysis.

CONCLUSION

This study suggested that women with AM have an increased risk of overall breast cancer and ER + breast cancer. MO was suggestively associated with the risk of overall breast cancer and ER- breast cancer.

Is physical inactivity and sedentary behavior associated with tumor stage in breast cancer patients? A cross-sectional study of Brazilian women

OBJECTIVE

A comparative analysis of the association between sedentary behavior versus physical activity levels and tumor staging in women with breast cancer.

METHODS

The present research adopted a cross-sectional study design to recruit a total of 55 adult and elderly women newly diagnosed with breast cancer for data collection and analysis. Inclusion criteria involved patients in procession of a formal approval for participation in the study by the treating physician and those not hitherto subjected to the first cycle of chemotherapy.

RESULTS

Physical activity levels did not influence the pathological stage of breast cancer (p=0.26) or histological tumor grade (p=0.07) in the analyzed subjects. However, there was a significant association between physical activity levels and responsiveness to hormones (epidermal growth factor receptor (HER2), p<0.05) in the analyzed subjects. Significant difference was detected in the histological tumor grade in relation to the mean time spent sitting during the weekend (p<0.05). However, sedentary behavior had no influence on the tumor stage (p>0.05).

CONCLUSION

Physical activity levels did not influence the tumor stage and histological tumor grade. Sedentary behavior had a significant influence on the histological tumor grade.

The relationship between tobacco and breast cancer incidence: A systematic review and meta-analysis of observational studies

Background

The effect of tobacco on breast cancer (BC) is controversial. The purpose of this study was to investigate the relationship between tobacco and BC.

Methods

A search was conducted in PubMed, EBSCO, Web of Science and Cochrane Library databases before February 2022. The adjusted odd ratio (OR) and corresponding 95% confidence interval (CI) were used to examine the relationship between active or passive smoking and BC risk.

Results

A total of 77 articles composed of 2,326,987 participants were included for this meta-analysis. Active (OR=1.15, 95% CI=1.11-1.20, p&lt;0.001) and passive (OR=1.17, 95% CI=1.09-1.24, p&lt;0.001) smoking increased the risk of BC in the female population, especially premenopausal BC (active smoking: OR=1.24, p&lt;0.001; passive smoking: OR=1.29, p&lt;0.001), but had no effect on postmenopausal BC (active smoking: OR=1.03, p=0.314; passive smoking: OR=1.13, p=0.218). Active smoking increased the risk of estrogen receptor-positive (ER+) BC risk (OR=1.13, p&lt;0.001), but had no effect on estrogen receptor-negative (ER-) BC (OR=1.08, p=0.155). The risk of BC was positively associated with the duration and intensity of smoking, negatively associated with the duration of smoking cessation. Active smoking increased the risk of BC in the multiparous population (OR=1.13, p&lt;0.001), but had no effect on the nulliparous population (OR=1.05, p=0.432), and smoking before the first birth (OR=1.22, 95% CI=1.17-1.27) had a greater impact on the risk of BC than smoking after the first birth (OR=1.08, 95% CI=1.04-1.12).

Conclusion

Smoking (active and passive) increased the risk of BC in women. The effect of smoking on BC was influenced by smoking-related factors (duration, intensity, years of quitting), population-related factors (fertility status), and BC subtypes.

Systematic Review Registration

identifier CRD42022322699.

Breast Cancer Incidence among Female Workers by Different Occupations and Industries: A Longitudinal Population-Based Matched Case-Control Study in Taiwan

BACKGROUND

Breast cancer is the leading cause of cancer incidence worldwide and in Taiwan. The relationship between breast cancer and occupational types remains unclear. This study aimed to investigate lifetime breast cancer incidence by different occupational industries among female workers in Taiwan.

METHODS

A population-based retrospective case-control study was conducted using three nationwide population-based databases. Matched case and control groups were identified with 1-to-4 exact matching among 103,047 female workers with breast cancer diagnosed in 2008-2017 and those without breast cancer. Their lifetime labor enrollment records were tracked using the National Labor Insurance Database, 1950-2017. Conditional logistic regression was used to analyze the association between types of occupational industries and risk of incident breast cancer.

RESULTS

Our study found slightly significant breast cancer risk among the following major occupational classifications: manufacturing (OR: 1.027, 95% CI: 1.011-1.043); wholesale and retail trade (OR: 1.068, 95% CI: 1.052-1.084); information and communication (OR: 1.074, 95% CI: 1.043-1.105); financial and insurance activities (OR: 1.109, 95% CI: 1.086-1.133); real estate activities (OR: 1.050, 95% CI: 1.016-1.085); professional, scientific, and technical activities (OR: 1.118, 95% CI: 1.091-1.145); public administration, defense, and social security (OR: 1.054, 95% CI: 1.023-1.087), education (OR: 1.199, 95% CI: 1.168-1.230); and human health and social work activities (OR: 1.125, 95% CI: 1.096-1.156).

CONCLUSIONS

Greater percentages of industrial occupations (i.e., manufacturing, wholesale and retail, or health professionals) were associated with slightly increased breast cancer risk. Further studies should investigate the possible risk factors among female workers in those industries with slightly higher incidence of breast cancer.

Recreational physical activity reduces breast cancer recurrence in female survivors of breast cancer: A meta-analysis

PURPOSE

The aim of this review was to systematically collect the published evidence to assess the effect of recreational physical activity (PA) in reducing breast cancer (BC) recurrence in female survivors.

METHODS

A bibliographic search was carried out in PubMed Medline, CINAHL Complete, Scopus and Lilacs until June 2021. We selected observational studies or clinical trials comprising women diagnosed with BC, in which the risk of recurrence of BC was measured before or after performing recreational PA. As a secondary outcome, we analyzed disease free survival for recurrence/disease-specific mortality. The methodological quality of observational studies was assessed with the Newcastle-Ottawa Scale and clinical trials with the PEDro scale. A random effects model was used to estimate the relative risks (RR) and their 95% confidence intervals (CI) to infer the results for any female survivor of BC. We performed separate meta-analyses for prediagnosis and postdiagnosis recreational PA.

RESULTS

Eleven studies were included, providing data from 29,677 surviving women with BC with an age range of 18-79 years old. Postdiagnosis recreational PA reduced the risk of BC recurrence by 16% (RR, 0.84; 95% CI: 0.78 to 0.91) and the risk of recurrence/disease-specific mortality by 23% (RR, 0.77; 95% CI: 0.66 to 0.93). Prediagnosis PA reduced the risk of BC by 18% (RR, 0.82; 95% CI: 0.74 to 0.91).

CONCLUSION

This systematic review with meta-analysis shows that recreational PA can be an interesting therapeutic tool to protect against recurrence of BC in female survivors.

The effect of exercise training on endothelial function in postmenopausal women with breast cancer under aromatase inhibitor therapy

BACKGROUND

Breast cancer is the leading non-cardiovascular cause of death in women. In endocrine receptor positive women, aromatase inhibitors (AI) are the therapy of choice despite the fact that a decrease in systemic estrogen levels may result in endothelial dysfunction and eventually in cardiovascular disease. In this study, we assessed whether exercise training (ET), which has repeatedly shown to lead to an improvement of endothelial dysfunction, will also exert this effect in postmenopausal women with AI treated breast cancer.

METHODS

Thirty two postmenopausal women with AI treated breast cancer were randomized to an intervention group (ET; 6 months, supervised training plus 6 months without intervention) or control group of usual care (UC; 12 months without intervention plus initial exercise counseling). Endothelial function was assessed via Reactive Hyperemia Index (RHI) measured non-invasively with the EndoPAT-System at baseline, 6 and 12 months.

RESULTS

After 6 months of supervised ET, changes in maximal exercise capacity were significantly greater in ET than in UC (∆W: 24.1 ± 11.5 vs. 1.1 ± 8.2 watts; p < 0.001). Even though 43.8% of all participants had endothelial dysfunction at baseline, there were no significant group differences in the changes of RHI between ET (∆RHI: -0.1 ± 1.04) and UC (0.02 ± 0.75; p = 0.323) after 6 months.

CONCLUSION

Even though ET led to significantly greater improvement in exercise capacity in postmenopausal women with AI treated breast cancer than exercise counseling only, it did not exert any measurable effects on endothelial dysfunction.