M. Boniol

Diabetes and breast cancer risk: a meta-analysis

Background:The potential of an increased risk of breast cancer in women with diabetes has been the subject of a great deal of recent research.Methods:A meta-analysis was undertaken using a random effects model to investigate the association between diabetes and breast cancer risk.Results:Thirty-nine independent risk estimates were available from observational epidemiological studies. The summary relative risk (SRR) for breast cancer in women with diabetes was 1.27 (95% confidence interval (CI), 1.16–1.39) with no evidence of publication bias. Prospective studies showed a lower risk (SRR 1.23 (95% CI, 1.12–1.35)) than retrospective studies (SRR 1.36 (95% CI, 1.13–1.63)). Type 1 diabetes, or diabetes in pre-menopausal women, were not associated with risk of breast cancer (SRR 1.00 (95% CI, 0.74–1.35) and SRR 0.86 (95% CI, 0.66–1.12), respectively). Studies adjusting for body mass index (BMI) showed lower estimates (SRR 1.16 (95% CI, 1.08–1.24)) as compared with those studies that were not adjusted for BMI (SRR 1.33 (95% CI, 1.18–1.51)).Conclusion:The risk of breast cancer in women with type 2 diabetes is increased by 27%, a figure that decreased to 16% after adjustment for BMI. No increased risk was seen for women at pre-menopausal ages or with type 1 diabetes.

Advanced breast cancer incidence following population-based mammographic screening

Background: Breast cancer mortality is declining in many Western countries. If mammography screening contributed to decreases in mortality, then decreases in advanced breast cancer incidence should also be noticeable. Patients and methods: We assessed incidence trends of advanced breast cancer in areas where mammography screening is practiced for at least 7 years with 60% minimum participation and where population-based registration of advanced breast cancer existed. Through a systematic Medline search, we identified relevant published data for Australia, Italy, Norway, Switzerland, The Netherlands, UK and the USA. Data from cancer registries in Northern Ireland, Scotland, the USA (Surveillance, Epidemiology and End Results (SEER), and Connecticut), and Tasmania (Australia) were available for the study. Criterion for advanced cancer was the tumour size, and if not available, spread to regional/distant sites. Results: Age-adjusted annual percent changes (APCs) were stable or increasing in ten areas (APCs of −0.5% to 1.7%). In four areas (Firenze, the Netherlands, SEER and Connecticut) there were transient downward trends followed by increases back to pre-screening rates. Conclusions: In areas with widespread sustained mammographic screening, trends in advanced breast cancer incidence do not support a substantial role for screening in the decrease in mortality.

Quantification of changes in breast cancer incidence and mortality since 1990 in 35 countries with Caucasian-majority populations

BACKGROUND Since 1985 considerable changes have taken place in the early detection and treatment of breast cancer. We quantified breast cancer trends for 35 countries with populations mainly of European ancestry. METHODS Incidence data were extracted from cancer registries and mortality data from World Health Organization database. Overall percentage change from 1990 to 2002 was quantified for all ages and for three different age-groups (35-49, 50-69 and >/=70 years of age). RESULTS The incidence percent change in women of all ages varied from 2.1% in Canada to 54.2% in Lithuania. Main increases in incidence were observed for women 50-69 years old, from 12.4% in Canada until 105.3% in Norway. Decreases in mortality of >20% were observed in nine countries. Mortality decreases were highest in women 35-49 years old and lowest in women >/=70 years. The magnitude of mortality decrease from 1990 to 2002 was not related to the mortality rate observed in 1990. CONCLUSIONS While increases in breast cancer incidence mainly concerned women >/=50 years, decreases in mortality were more marked in women 35-49 years old. Large disparities in changes in mortality rates probably reflect differences in detection of and management of breast cancer.

Changes in breast cancer incidence and mortality in middle-aged and elderly women in 28 countries with Caucasian majority populations

BACKGROUND Mammography screening and menopause hormone therapy is essentially offered to women 50-69 years old. METHODS In 28 European ancestry countries, we quantified changes in breast cancer incidence and mortality using a joinpoint regression analysis from 1960 until last year of available data. RESULTS Since 1960, increases in incidence often in the order of 2%-3% per year occurred in all countries, mainly in women 50-69 years old whose incidence in eight countries surpassed the incidence in women 70 years old and more. In 10 countries, a decrease in incidence in women >or=70 years was noticeable in the last years of observation, but the magnitude of this decrease was far from matching the magnitude of the increases observed in the 50-69 age-group. In the beginning of years 2000s, a persistent decrease in mortality of approximately 2% per year was observed in women 50-69 years old in most countries and parallel declines in mortality were observed in women 70 years or more. CONCLUSIONS In years 2000s, in a number of countries, the incidence of breast cancer has become greater in middle-aged women than in older women. If trends remain unchanged, the same phenomenon is likely to happen in other countries.

Trends in colorectal cancer mortality in Europe: retrospective analysis of the WHO mortality database

Objective To examine changes in colorectal cancer mortality in 34 European countries between 1970 and 2011. Design Retrospective trend analysis. Data source World Health Organization mortality database. Population Deaths from colorectal cancer between 1970 and 2011. Profound changes in screening and treatment efficiency took place after 1988; therefore, particular attention was paid to the evolution of colorectal cancer mortality in the subsequent period. Main outcomes measures Time trends in rates of colorectal cancer mortality, using joinpoint regression analysis. Rates were age adjusted using the standard European population. Results From 1989 to 2011, colorectal cancer mortality increased by a median of 6.0% for men and decreased by a median of 14.7% for women in the 34 European countries. Reductions in colorectal cancer mortality of more than 25% in men and 30% in women occurred in Austria, Switzerland, Germany, the United Kingdom, Belgium, the Czech Republic, Luxembourg, and Ireland. By contrast, mortality rates fell by less than 17% in the Netherlands and Sweden for both sexes. Over the same period, smaller or no declines occurred in most central European countries. Substantial mortality increases occurred in Croatia, the former Yugoslav republic of Macedonia, and Romania for both sexes and in most eastern European countries for men. In countries with decreasing mortality, reductions were more important for women of all ages and men younger than 65 years. In the 27 European Union member states, colorectal cancer mortality fell by 13.0% in men and 27.0% in women, compared with corresponding reductions of 39.8% and 38.8% in the United States. Conclusion Over the past 40 years, there has been considerable disparity in the level of colorectal cancer mortality between European countries, as well as between men and women and age categories. Countries with the largest reductions in colorectal cancer mortality are characterised by better accessibility to screening services, especially endoscopic screening, and specialised care.

Population attributable fraction of infection-related cancers in Korea

BACKGROUND A number of infectious agents have been classified as human carcinogens. The purpose of the current study was to provide an evidence-based assessment of the burden of infection-related cancers in the Korean population. MATERIALS AND METHODS The population attributable fraction was calculated using infection prevalence data from 1990 or earlier, relative risk estimates from meta-analyses using mainly Korean studies and national data on cancer incidence and mortality for the year 2007. RESULTS The fractions of all cancers attributable to infection were 25.1% and 16.8% for cancer incidence in men and women, and 25.8% and 22.7% of cancer mortality in men and women, respectively. Among infection-related cancers, Helicobacter pylori was responsible for 56.5% of cases and 45.1% of deaths, followed by hepatitis B virus (HBV) (23.9% of cases and 37.5% of deaths) and human papillomavirus (HPV) (11.3% of cases and 6% of deaths) and then by hepatitis C virus (HCV) (6% of cases and 9% of deaths). Over 97% of infection-related cancers were attributable to infection with H. pylori, HBV, HCV and HPV. CONCLUSION Up to one-quarter of cancer cases and deaths would be preventable through appropriate control of infectious agents in Korea.

Effect of vitamin D supplementation on non-skeletal disorders: a systematic review of meta-analyses and randomised trials

Randomised trials reported up to Dec 31, 2012, did not confirm that vitamin D supplementation could protect from non-skeletal health conditions affecting adults, as was expected on the basis of data from observational studies. To examine whether the more recently published meta-analyses and trials would change past conclusions, we systematically reviewed meta-analyses of vitamin D supplementation and non-skeletal disorders published between Jan 1, 2013, and May 31, 2017, that included study participants of all ages, including pregnant women. We also searched for randomised trials not included in meta-analyses. We identified 87 meta-analyses, of which 52 were excluded because they contained less recent literature or were of suboptimal quality. We retrieved 202 articles on trials that were not included in meta-analyses. Recent meta-analyses reinforce the finding that 10-20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people. Although vitamin D doses were greater than those assessed in the past, we found no new evidence that supplementation could have an effect on most non-skeletal conditions, including cardiovascular disease, adiposity, glucose metabolism, mood disorders, muscular function, tuberculosis, and colorectal adenomas, or on maternal and perinatal conditions. New data on cancer outcomes were scarce. The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation. The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations. There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions, including chronic inflammation, despite use of increased doses of vitamin D, strengthening the hypothesis that low vitamin D status is a consequence of ill health, rather than its cause. We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections, which would reduce the risk of death in debilitated individuals. We identified many meta-analyses of suboptimal quality, which is of concern. Future systematic reviews on vitamin D should be based on data sharing so that data for participants with the same outcomes measured in the same way can be pooled to generate stronger evidence.

Decline in breast cancer incidence in the Flemish region of Belgium after a decline in hormonal replacement therapy

BACKGROUND Breast cancer incidence rate in Belgian women was as high as 152.7 for 100 000 in 2003 (adjusted on European population). We made an estimation of the contribution of hormone replacement therapy (HRT) on breast cancer incidence from 1999 to 2005 in women aged 50-69 years in Flanders. METHODS Breast cancer data were extracted from the Belgium Cancer Registry. Drug consumption was computed from drug sales data. The fraction of breast cancers attributable to HRT was calculated by year, using the relative risks of the Million Women Study in the UK. RESULTS The proportion of women aged 50-69 years using HRT in Flanders increased since 1992, peaked at 20% in 2001, then decreased to 8% in 2008. The incidence of breast cancer in 100 000 women aged 50-69 years in Flanders increased from 332.8 in 1999 to 407.9 in 2003, then decreased to 366.1 in 2005; the variations were mostly noticeable for tumors <20 mm in size. The fraction of breast cancers attributed to HRT peaked at 11% in 2001 and decreased afterward. CONCLUSION The high level of breast cancer observed in the years 2001-2003 in Flanders can be partly attributed to the use of HRT. Since participation to mammography screening of Flemish women aged 50-69 years was still on the rise in 2003 and never exceeds 62%, the decrease in breast cancer incidence was likely to be due to the decrease in HRT use and not to screening saturation.

Effectiveness of and overdiagnosis from mammography screening in the Netherlands: population based study

Abstract Objective To analyse stage specific incidence of breast cancer in the Netherlands where women have been invited to biennial mammography screening since 1989 (ages 50-69) and 1997 (ages 70-75), and to assess changes in breast cancer mortality and quantified overdiagnosis. Design Population based study. Setting Mammography screening programme, the Netherlands. Participants Dutch women of all ages, 1989 to 2012. Main outcome measures Stage specific age adjusted incidence of breast cancer from 1989 to 2012. The extra numbers of in situ and stage 1 breast tumours associated with screening were estimated by comparing rates in women aged 50-74 with those in age groups not invited to screening. Overdiagnosis was estimated after subtraction of the lead time cancers. Breast cancer mortality reductions during 2010-12 and overdiagnosis during 2009-11 were computed without (scenario 1) and with (scenario 2) a cohort effect on mortality secular trends. Results The incidence of stage 2-4 breast cancers in women aged 50 or more was 168 per 100 000 in 1989 and 166 per 100 000 in 2012. Screening would be associated with a 5% mortality reduction in scenario 1 and with no influence on mortality in scenario 2. In both scenarios, improved treatments would be associated with 28% reductions in mortality. Overdiagnosis has steadily increased over time with the extension of screening to women aged 70-75 and with the introduction of digital mammography. After deduction of clinical lead time cancers, 32% of cancers found in women invited to screening in 2010-12 and 52% of screen detected cancers would be overdiagnosed. Conclusions The Dutch mammography screening programme seems to have little impact on the burden of advanced breast cancers, which suggests a marginal effect on breast cancer mortality. About half of screen detected breast cancers would represent overdiagnosis.

Occupational UV exposure in French outdoor workers

Objectives: Occupational ultraviolet (UV) exposure was evaluated in a population-based sample in France. Methods: A random survey was conducted in 2012 in individuals aged 25 to 69 years. The median daily standard erythemal UV dose (SED) was estimated from exposure time and place and matched to satellite UV records. Results: A total of 889 individuals were exposed to solar UV with highest doses observed among gardeners (1.19 SED), construction workers (1.13 SED), agricultural workers (0.95 SED), and culture/art/social science workers (0.92 SED). Information and communication technology, industry, and transport workers were highly exposed (>0.70 SED). Significant factors associated with high occupational UV exposure were sex (P < 0.0001), phototype (P = 0.0003), and taking lunch outdoors (P < 0.0001). Conclusions: This study identified not only expected occupations with high UV exposure but also unexpected occupations with high exposures. This could serve as a basis for future prevention.