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Weight Change and Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis.
Variation de poids et risque de cancer colorectal : une revue systématique et méta-analyse
Karahalios A et al,. Am J Epidemiol. 2015.
Results from cohort studies of adult weight gain and risk of colorectal cancer are inconsistent. We conducted a
systematic review and meta-analysis of prospective studies assessing the association of change in weight/body
mass index with colorectal cancer risk. We searched Scopus and Web of Science up to June 2014 and
supplemented the search with manual searches of the reference lists of the identified articles. Thirteen studies
published between 1997 and 2014 were pooled by using a random-effects model, and potential heterogeneity
was explored by fitting meta-regression models. The highest weight gain category, measured by weight/body
mass index, compared with a reference category, was associated with increased risk of colorectal cancer (hazard
ratio (HR) = 1.16, 95% confidence interval (CI): 1.08, 1.24), whereas no association was found for weight loss
(HR = 0.96, 95% CI: 0.89, 1.05). There was no suggestion of heterogeneity across studies. For dose response, a
5-kg weight gain was associated with a slightly increased risk of colorectal cancer (HR = 1.03, 95% CI: 1.02,
1.05), with some heterogeneity observed (I2 = 42%; P = 0.02), which was partially explained by sex (ratio of
HRs = 1.03, 95% CI: 1.00, 1.07). In this meta-analysis, gain in weight/body mass index was positively
associated with colorectal cancer risk.
Ambient particulate matter and lung cancer incidence and mortality: a meta-analysis of
prospective studies
Matière particulaire ambiante et incidence et mortalité du cancer du poumon: une méta-analyse d'études
prospectives
Cui. P et al., Eur J Public Health. 2015 Apr
Chronic exposure to ambient particulate matter (PM) has been suggested to be associated with an increased risk
of lung cancer, but the results were inconsistent. We performed a systematic review and meta-analysis of
prospective studies to assess the association between exposure to PM and the incidence and mortality of lung
cancer in adults.
METHODS:
We searched PUBMED and EMBASE databases for prospective cohort studies that evaluated the association
between PM2.5 (diameter < 2.5 μm), PM10 (diameter < 10 μm) and lung cancer incidence and mortality.
Relative risks (RRs) and 95% confidence interval (CI) were calculated using fixed-effect or random-effects
models when appropriate.
RESULTS:
We initially identified 1987 citations, and 19 prospective cohort studies were finally included in our meta-
analysis. The pooled adjusted RRs for lung cancer mortality were 1.09 (95% CI: 1.06-1.11; I(2) = 18.3%, P =
0.26) for 10 µg/m(3) increase in the concentration of PM2.5 (12 studies), and 1.05 (95% CI: 1.03-1.07; I(2) =
41.9%, P = 0.11) for 10 µg/m(3) increase in the concentration of PM10 (seven studies). The increased risk of
lung cancer mortality associated with PM2.5 and PM10 was consistent across most subgroups. PM10 (three
studies) and PM2.5 (two studies) were not found to be significantly associated with lung cancer incidence.
CONCLUSIONS:
Ambient PM2.5 and PM10 pollutions are prospectively associated with a significantly increased risk of lung
cancer mortality. More studies addressing the association between PM and lung cancer incidence are required.