Vitamin D and breast cancer incidence: a meta-analysis.

Abstract Study Objectives To investigate the association between sleep duration and breast cancer incidence, we examined the association in a large UK prospective study and conducted a meta-analysis of prospective studies. Methods In the Million Women Study, usual sleep duration over a 24-h period was collected in 2001 for 713,150 participants without prior cancer, heart problems, stroke, or diabetes (mean age = 60 years). Follow-up for breast cancer was by record linkage to national cancer registry data for 14.3 years on average from the 3-year resurvey. Cox regression models yielded multivariable-adjusted breast cancer relative risks (RR) and 95% confidence intervals (CIs) for sleep duration categories. Published prospective studies of sleep duration and breast cancer risk were included in a meta-analysis, which estimated the inverse-variance weighted average of study-specific log RRs for short and for long versus average duration sleep. Results After excluding the first 5 years to minimize reverse causation bias in the Million Women Study, 24,476 women developed breast cancer. Compared with 7–8 h of sleep, the RRs for <6, 6, 9, and >9 h of sleep were 1.01 (95% CI, 0.95–1.07), 0.99 (0.96–1.03), 1.01 (0.96–1.06), and 1.03 (0.95–1.12), respectively. In a meta-analysis of 14 prospective studies plus the Million Women Study, including 65,410 breast cancer cases, neither short (RR < 7 h = 0.99 [0.98–1.01]) nor long (RR > 8 h = 1.01 [0.98–1.04]) versus average duration sleep was associated with breast cancer risk. Conclusions The totality of the prospective evidence does not support an association between sleep duration and breast cancer risk.

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Relationship between particulate matter exposure and female breast cancer incidence and mortality: a systematic review and meta-analysis

International Archives of Occupational and Environmental Health ◽

10.1007/s00420-020-01573-y ◽

2020 ◽

Author(s):

Qing Guo ◽

Xi Wang ◽

Yue Gao ◽

Jun Zhou ◽

Chenyin Huang ◽

...

Keyword(s):

Breast Cancer ◽

Systematic Review ◽

Particulate Matter ◽

Cancer Incidence ◽

Meta Analysis ◽

Breast Cancer Incidence ◽

Female Breast Cancer ◽

Female Breast ◽

Incidence And Mortality ◽

Particulate Matter Exposure

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Sleep duration and breast cancer incidence: results from the million women study and a meta-analysis of published prospective studies

Sleep Medicine ◽

10.1016/j.sleep.2019.11.1171 ◽

2019 ◽

Vol 64 ◽

pp. S421-S422

Author(s):

A.T.Y. Wong ◽

A.K. Heath ◽

G.K. Reeves ◽

S. Floud ◽

V. Beral ◽

...

Keyword(s):

Breast Cancer ◽

Sleep Duration ◽

Cancer Incidence ◽

Prospective Studies ◽

Meta Analysis ◽

Breast Cancer Incidence

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Metformin and breast cancer risk: A meta-analysis and critical literature review.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.27_suppl.25 ◽

2012 ◽

Vol 30 (27_suppl) ◽

pp. 25-25

Author(s):

Nananda Col ◽

Leslie Ochs ◽

Vicky Springmann ◽

Aaron K Aragaki ◽

Rowan T. Chlebowski

Keyword(s):

Breast Cancer ◽

Breast Cancer Risk ◽

Cancer Risk ◽

Literature Review ◽

Cancer Incidence ◽

Invasive Breast Cancer ◽

Meta Analysis ◽

Breast Cancer Incidence ◽

Cochrane Library ◽

Study Quality

25 Background: Observational studies have suggested that metformin, commonly used for diabetes treatment that increases insulin sensitivity and improves glycemic control, decreases the incidence of several common cancers. However, findings regarding metformin and breast cancer incidence have been mixed. To explore this issue, a systematic literature review and meta-analysis were performed with a focus on potential biases. Methods: We conducted a comprehensive literature search for all pertinent studies addressing metformin use and breast cancer risk by searching Pub Med, Cochrane Library, Scopus (which includes Embase, ISI Web of Science) using the Mesh terms: "metformin" or "biguanides" or "diabetes mellitus, type 2/therapy" and "cancer" or "neoplasms". When multiple hazard ratios (HR) or odds ratio (OR) were reported, the most adjusted estimate was used in the base-case analysis. We pooled the adjusted HR using and performed sensitivity analyses on duration of metformin use (> or < 3 years use), study quality (assessed using the GRADE system), and initial observation year of the cohort (before vs after 1997). Results: From a total of 421 citations, 13 full-text articles were considered, and 7 independent studies were included. All were observational (4 cohort and 3 case control). Our combined OR for metformin association with invasive breast cancer of all 7 studies was 0.83 (95% CI, 0.71-0.97). Funnel plot analyses did not suggest publication bias. Stronger associations were found when analyses were limited to studies estimating the impact of longer metformin duration (OR = 0.75. 95% CI, 0.62-0.91) or among studies that began observing their cohort before 1997 (OR=0.68. 95% CI, 0.55-0.84). Stratification according to study quality did not affect the combined OR but higher quality studies had smaller CI and achieved statistical significance. Interpretation is limited by the observational nature of reports and different comparison groups. Conclusions: Our analyses support a protective effect of metformin on invasive breast cancer incidence among postmenopausal women with diabetes. Clinical trials are needed to determine whether metformin reduces breast cancer risk.

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