Sunlight exposure during leisure activities and risk of prostate cancer in Montréal, Canada, 2005-2009

Association between sunlight exposure and risk of prostate cancer: a systematic review and meta-analysis

BACKGROUND

The prevalence of prostate cancer (PC) is increasing worldwide. An association between sunlight exposure and PC risk has been described by a previously published meta-analysis, although the level of statistical significance was not reached. We have, therefore, performed an updated systematic review and meta-analysis to further elucidate this potential connection.

METHODS

To identify relevant articles, we conducted an in-depth search of 4 electronic databases (PubMed, Embase, the Web of Science and Scopus) for manuscripts published prior to March 2021. A random-effects model was used to compute a meta-estimate of the effects of sunlight exposure on risk of PC.

RESULTS

Of the 5680 articles that were initially identified in our search, 12 observational epidemiological studies encompassing 29 282 cases of PC were selected for inclusion in the qualitative systematic review. Of these, two case-control studies were excluded from the meta-analysis. Comparing highest-to-lowest exposure, personal sunlight exposure was significantly associated with a decreased risk of PC [odds ratio (OR) = 0.67, 95% CI: 0.57-0.78] in a random-effects meta-analysis; however, high heterogeneity was present (I2 = 85.9%). Comparing moderate-to-lowest exposure, there was a non-significant relationship between personal sunlight exposure and the risk of PC (OR = 0.87, 95% CI: 0.68-1.10; I2 = 74.0%).

CONCLUSIONS

Our findings indicate that exposure to sunlight may protect against PC. The limitations of our research are occurrence of publication bias and a substantial heterogeneity due to a diversity of criteria for measuring sunlight exposure.

Awareness about proper use of sunscreen in people of color: A Jordanian-based survey

INTRODUCTION

The use of sunscreen is an important preventive measure against skin cancer and treatment for other skin conditions. There is evidence pointing to lack awareness and misconceptions regarding use of Sunscreen. This is especially evident in populations with skin of color (POC).

METHODS

This is a cross-sectional study of 2000 individuals. A structured questionnaire was designed to collect data on general knowledge and use of sunscreen as well as reasons for stopping use of sunscreen.

RESULTS

The results of this study indicate a clear deficiency in the use and knowledge about sunscreen among Jordanians. Females are using sunscreen more than males. However, the use of sunscreen is inadequate in many aspects including timing of application, frequency of use, and amount used among other things. There is an obvious lack of knowledge about sunscreen as shown by lack of awareness about benefits of use in various times of the year, use in children, use for all skin types, and several misconceptions among other knowledge gaps. Main reasons for stopping sunscreen include side effects, cost, and being not suitable for skin. Awareness about sunscreen can be improved by proper counseling by healthcare professionals and utilization of various media platforms.

CONCLUSIONS

The use of sunscreen is inadequate in this population of color (POC). Lack of proper counseling, failure to read use instructions can contibute to inadequate use of sunscreen. Risks and benefits of sunscreen should be explained by medical professionals. The media should be more utilized to disseminate such knowledge.

Occupation as a predictor of prostate cancer screening behaviour in Canada

OBJECTIVES

If prostate cancer screening practices relate to occupation, this would have important implications when studying the aetiological role of workplace exposures on prostate cancer. We identified variations in screening by occupation among men in Montreal, Canada (2005-2012).

METHODS

Prostate specific antigen testing and digital rectal examination (ever-screened and frequency of screening, previous five years) were examined among population controls from the Prostate Cancer & Environment Study. Face-to-face interviews elicited lifestyle and occupational histories. Multivariable logistic regression was used to estimate the odds of ever-screening for the longest-held occupation, adjusting for potential confounders. Negative binomial models were used to examine relationships with screening frequency.

RESULTS

Among 1989 controls, 81% reported ever having had a prostate specific antigen test, and 77% a digital rectal examination. Approximately 40% of men reported having a prostate specific antigen test once a year, on average. Compared with those in management or administrative jobs, men in primary industry (odds ratio 0.26, 95% confidence interval 0.10-0.65), construction (0.44, 0.25-0.79), machining (0.45, 0.21-0.97), and teaching (0.37, 0.20-0.70) were less likely to have undergone prostate specific antigen screening. Results were similar when considering the most recent job.

CONCLUSIONS

Our findings highlight substantial variations in prostate cancer screening by occupation. Men in occupations where carcinogen exposures are more common are less likely to participate in prostate screening activities. This could be an important source of bias, and occupational studies of prostate cancer should account for screening practices.

Residential greenness and risk of prostate cancer: A case-control study in Montreal, Canada

BACKGROUND

Recent studies suggest that exposure to greenness favors several health outcomes. We assessed whether living in the proximity of greener areas was related to prostate cancer incidence in a population-based case-control study in Montreal, Canada.

MATERIALS AND METHODS

Interviews eliciting lifetime addresses were conducted with 1933 prostate cancer cases diagnosed in 2005-2009 and 1994 population controls. Odds ratios (OR) and 95% confidence intervals (CI) estimated the association between residential greenness, both at recruitment (2005-2009) and about ten years prior (1996), defined by the normalized difference vegetation index (NDVI) around the home, and prostate cancer risk. Three models were developed adjusting for age, individual characteristics, and individual and ecological characteristics, estimating relative risk in relation to an interquartile range (IQR) increase of the NDVI.

RESULTS

We observed inverse associations between greenness measured within home buffers of 150m, 300m, 500m and 1000m, at both time points, and risk of prostate cancer, independently of individual and ecological characteristics. For instance, using a buffer of 300m, the OR for an IQR increase of 0.11 in NDVI at the time of recruitment was 0.82 (95%CI 0.74-0.92). The corresponding OR for an IQR increase of 0.15 in NDVI in 1996 was 0.86 (95%CI 0.74-1.00). There were little differences in risks according to buffer size, the time point of exposure, when considering prostate cancer aggressiveness, or when restricting controls to men recently screened for prostate cancer to reduce the likelihood of undiagnosed cancer among them.

CONCLUSION

Men living in greener areas, either recently or about a decade earlier, had lower risks of prostate cancer, independently of socio-demographic and lifestyle factors. These observations are novel and require confirmation.

Association between lifetime alcohol consumption and prostate cancer risk: A case-control study in Montreal, Canada

BACKGROUND

Alcohol intake may increase the risk of prostate cancer (PCa). Many previous studies harbored important methodological limitations.

METHODS

We conducted a population-based case-control study of PCa comprising 1933 cases and 1994 controls in Montreal, Canada. Lifetime alcohol consumption was elicited, by type of beverage, during in-person interviews. Odds ratios (OR) and 95% confidence intervals (CI) assessed the association between alcohol intake and PCa risk, adjusting for potential confounders and considering the subjects' PCa screening history.

RESULTS

We observed a weak, non-significant positive association between high consumption of total alcohol over the lifetime and risk of high-grade PCa (OR=1.18, 95% CI 0.81-1.73). Risk estimates were more pronounced among current drinkers (OR=1.40, 95%CI 1.00-1.97), particularly after adjusting for the timing of last PCa screening (OR=1.52, 95%CI 1.07-2.16). These associations were largely driven by beer consumption. The OR for high-grade PCa associated with high beer intake was 1.37 (95%CI 1.00-1.89); it was 1.49 (95%CI 0.99-2.23) among current drinkers and 1.68 (95% CI 1.10-2.57) after adjusting for screening recency. High cumulative consumption of spirits was associated with a lower risk of low-grade PCa (OR=0.75, 95%CI 0.60-0.94) but the risk estimate no longer achieved statistical significance when restricting to current users. No association was found for wine consumption.

CONCLUSION

Findings add to the accumulating evidence that high alcohol consumption increases the risk of high-grade PCa. This association largely reflected beer intake in our population, and was strengthened when taking into account PCa screening history.

Metabolic syndrome and prostate cancer risk in a population-based case-control study in Montreal, Canada

Background

The role of metabolic syndrome (MetS) in prostate cancer risk is still debated. We investigated it in a large population-based case–control study.

Methods

Cases were 1937 men with incident prostate cancer, aged ≤75 years, diagnosed across French hospitals in the Montreal area between 2005 and 2009. Concurrently, 1995 population controls from the same residential area and age distribution were randomly selected from electoral list of French-speaking men. Detailed lifestyle and medical histories, and anthropometric measures, were collected during in-person interviews. Prevalence of MetS components (type 2 diabetes, high blood pressure, dyslipidemia and abdominal obesity) was estimated at 2 years before diagnosis for cases/ interview for controls, and at ages 20, 40, 50 and 60. Logistic regression was used to estimate odds ratios (OR) and 95 % confidence intervals for the association between MetS and prostate cancer risk.

Results

A history of MetS (≥3 components vs <3) was associated with a reduced risk of prostate cancer (OR = 0.70 [0.60, 0.82]) after considering potential confounders. The negative association was particularly pronounced with a young age (≤40 years) at MetS onset (OR = 0.38 [0.16-0.89]), did not vary according to prostate cancer aggressiveness, and was only partly explained by the presence of type 2 diabetes. A risk decrease was observed with the number of MetS components, suggesting a synergistic interaction of the components.

Discussion

The observed negative association, consistent with results from other North American populations undergoing regular prostate cancer screening, underlines the importance of considering PSA-testing when studying the MetS-prostate cancer association.

Conclusions

Findings from this study are consistent with an inverse association between MetS and prostate cancer risk.