Alice Koechlin

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.

Cancer Incidence in Nigeria: A Report from Population-based Cancer Registries

INTRODUCTION Cancer has become a major source of morbidity and mortality globally. Despite the threat that cancer poses to public health in sub-Saharan Africa (SSA), few countries in this region have data on cancer incidence. In this paper, we present estimates of cancer incidence in Nigeria based on data from 2 population-based cancer registries (PBCR) that are part of the Nigerian national cancer registry program. MATERIALS AND METHODS We analyzed data from 2 population based cancer registries in Nigeria, the Ibadan Population Based Cancer Registry (IBCR) and the Abuja Population Based Cancer Registry (ABCR) covering a 2 year period 2009-2010. Data are reported by registry, gender and in age groups. We present data on the age specific incidence rates of all invasive cancers and report age standardized rates of the most common cancers stratified by gender in both registries. RESULTS The age standardized incidence rate for all invasive cancers from the IBCR was 66.4 per 100000 men and 130.6 per 100000 women. In ABCR it was 58.3 per 100000 for men and 138.6 per 100000 for women. A total of 3393 cancer cases were reported by the IBCR. Of these cases, 34% (1155) were seen among males and 66% (2238) in females. In Abuja over the same period, 1128 invasive cancers were reported. 33.6% (389) of these cases were in males and 66.4% (768) in females. Mean age of diagnosis of all cancers in men for Ibadan and Abuja were 51.1 and 49.9 years respectively. For women, mean age of diagnosis of all cancers in Ibadan and Abuja were 49.1 and 45.4 respectively. Breast and cervical cancer were the commonest cancers among women and prostate cancer the most common among men. Breast cancer age standardized incidence rate (ASR) at the IBCR was 52.0 per 100000 in IBCR and 64.6 per 100000 in ABCR. Cervical cancer ASR at the IBCR was 36.0 per 100000 and 30.3 per 100000 at the ABCR. The observed differences in incidence rates of breast, cervical and prostate cancer between Ibadan and Abuja, were not statistically significant. CONCLUSION Cancer incidence data from two population based cancer registries in Nigeria suggests substantial increase in incidence of breast cancer in recent times. This paper highlights the need for high quality regional cancer registries in Nigeria and other SSA countries.

Mammography Screening and Breast Cancer Mortality in Sweden

BACKGROUND Swedish women aged 40-69 years were gradually offered regular mammography screening since 1974, and nationwide coverage was achieved in 1997. We hypothesized that this gradual implementation of breast cancer screening would be reflected in county-specific mortality patterns during the last 20 years. METHODS Using data from the Swedish Board of Health and Welfare from 1960 to 2009, we used joinpoint regression to analyze breast cancer mortality trends in women aged 40 years and older (1,286,000 women in 1995-1996). Poisson regression models were used to compare observed mortality trends with expected trends if screening had resulted in breast cancer mortality reductions of 10%, 20%, or 30% among women screened during 18 years of follow-up after the introduction of screening. All statistical tests were two-sided. RESULTS From 1972 to 2009, breast cancer mortality rates in Swedish women aged 40 years and older declined by 0.98% annually, from 68.4 to 42.8 per 100,000, and it continuously declined in 14 of the 21 Swedish counties. In three counties, breast cancer mortality declined sharply during or soon after the implementation of screening; in two counties, a steep decline started at least 5 years after screening was introduced; and in two counties, breast cancer mortality increased after screening started. In counties in which screening started in 1974-1978, mortality trends during the next 18 years were similar to those before screening started, and in counties in which screening started in 1986-1987, mortality increased by approximately 12% (P = .007) after the introduction of screening compared with previous trends. In counties in which screening started in 1987-1988 and in 1989-1990, mortality declined by approximately 5% (P = .001) and 8% (P < .001), respectively, after the introduction of screening. Conclusion County-specific mortality statistics in Sweden are consistent with studies that have reported limited or no impact of screening on mortality from breast cancer.

Endogenous and exogenous testosterone and the risk of prostate cancer and increased prostate-specific antigen (PSA) level: a meta-analysis

To review and quantify the association between endogenous and exogenous testosterone and prostate‐specific antigen (PSA) and prostate cancer.

Relation between breast cancer and high glycemic index or glycemic load : a meta-analysis of prospective cohort studies

Breast cancer is the commonest form of cancer in women worldwide. It has been suggested that chronic hyperinsulinemia associated with insulin resistance plays a role in breast cancer etiology. To test the hyperinsulinemia hypothesis, a dietary pattern associated with a high glycemic index and glycemic load, both proxies for chronic hyperinsulinemia, should be associated with an increased risk of breast cancer. A meta-analysis restricted to prospective cohort studies was undertaken using a random effects model with tests for statistical significance, publication bias and heterogeneity. The metric for analysis was the risk of breast cancer in the highest relative to the lowest glycemic index and glycemic load dietary pattern. A dietary pattern with a high glycemic index was associated with a summary relative risk (SRR) of 1.05 (95% CI: 1.00, 1.11), and a high glycemic load with a SRR of 1.06 (95% CI: 1.00, 1.13). Adjustments for body mass index [BMI], physical activity and other lifestyle factors did not influence the SRR, nor did menopausal status and estrogen receptor status of the tumor. In conclusion, the current evidence supports a modest association between a dietary pattern with high glycemic index or glycemic load and the risk of breast cancer.

The forthcoming inexorable decline of cutaneous melanoma mortality in light-skinned populations

BACKGROUND Reasons underlying time changes in cutaneous melanoma mortality in light-skinned populations are not well understood. An analysis of long-term time trends in melanoma mortality was carried out after regrouping countries in homogeneous regions. METHODS Using the World Health Organisation (WHO) mortality database, age-period-cohort models were fitted for seven regions where the majority of population is light-skinned. Cohort effects are denoted as changes in rates occurring at different times in steadily older age groups. Period effects are denoted as changes in rates occurring simultaneously in several age groups. RESULTS Cohort effects better explained changes in melanoma mortality over time than period effects. Lifetime risk to die from melanoma increased in successive generations from 1875 until a peak year. Peak years were for subjects born in 1936-1940 in Oceania, 1937-1943 in North America, 1941-1942 in Northern Europe, 1945-1953 in the United Kingdom (UK) and Ireland, 1948 in Western Europe and 1957 in Central Europe. After peak years, lifetime risk of melanoma death gradually decreased in successive generations and risks of subjects born in 1990-1995 were back to risk levels observed for subjects born before 1900-1905. In Southern Europe, birth years with highest lifetime risk of melanoma death have not yet been attained. As time passes, melanoma deaths will steadily rarefy in younger age groups and concentrate in older age groups, for ultimately fade away after 2040-2050. CONCLUSION Independently from screening or treatment, over next decades, death from melanoma is likely to become an increasingly rare event. The temporary epidemic of fatal melanoma was most probably due to excessive UV-exposure of children that prevailed in 1900-1960, and mortality decreases would be due to progressive reductions in UV-exposure of children over the last decades.

Mouthwash use and the prevention of plaque, gingivitis and caries

Careful quantitative assessment of data regarding use of mouthwash and risk of common oral conditions reveals that there is a clear evidence of benefi t from use in terms of reducing the risk of dental plaque, gingivitis, dental caries and that there are no major adverse effects including no evidence of an increased risk of oral cancer among users of mouthwash containing alcohol. Despite limitations in the quality of many studies conducted, there is a signifi cant reduction of both dental plaque and gingivitis associated with use of mouthwash preparations containing chlorhexidine or essential oils as an adjunct to standard care. The effect of mouthwash containing essential oils on both plaque and gingivitis is less than chlorhexidine in studies of less than 3 months duration but improves with increasing duration of use and equals or exceeds the effect of chlorhexidine when use is 6 months of longer. Mouthwash preparations containing cetylpyridinium or triclosan may also be effective, but less than the two former, while mouthwashes containing delmopinol are not effective for plaque and gingivitis control. How- ever, there is a large degree of heterogeneity and strong evidence of publication bias: there is a lack of small studies with a small effect of mouthwash. This results in a biased estimate of effect (over-estimated) because there is a tendency to publish mainly positive studies (those showing a strong decrease). Compared with fl uoride toothpaste used alone, topical fl uorides (mouthrinses, gels or varnishes) used in addition to fl uo- ride toothpaste reduce caries by 10% on average. Topical fl uorides (mouthrinses, gels, or varnishes) used in addition to fl uo- ride toothpaste achieve a modest reduction in caries compared to toothpaste used alone. No conclusions about any adverse effects can be reached, because such data were rarely reported in the trials. It is possible to conclude that mouthwash contain- ing fl uoride is a useful adjunct to fl uoridated toothpaste in reducing caries in children. As regards oral malignancy, quantitative analysis of mouthwash use and oral malignancy revealed no statistically signifi - cant association between mouthwash use and risk of oral cancer including no signifi cant trend in risk with increasing daily use; and no association between use of mouthwash containing alcohol and oral cancer risk. Most recent estimates of the population attributable risk for alcohol consumption and oral cancer put the fi gure at 1%. The dose of acetaldehyde from mouthwash is minute compared to that from other sources notable cigarette smoking, alco- hol drinking and certain foodstuffs including yoghurt and peas. It is extremely unlikely from a theoretical viewpoint that mouthwash could be a cause of oral cancer and this is substantiated from the lack of evidence of carcinogenicity found in epidemiological studies in humans. In summary, there is evidence supporting the use of mouthwashes in terms of preventing or reducing the risk of develop- ing a number of common conditions notably dental plaque, gingivitis and dental caries without any adverse effects. There is also evidence that mouthwash use does not increase the risk of oral cancer even when it contains a signifi cant percentage of alcohol. Mouthwash use makes a signifi cant contribution to public health.

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.

A general model to predict individual exposure to solar UV by using ambient irradiance data

Excessive exposure to solar ultraviolet (UV) is the main cause of skin cancer. Specific prevention should be further developed to target overexposed or highly vulnerable populations. A better characterisation of anatomical UV exposure patterns is however needed for specific prevention. To develop a regression model for predicting the UV exposure ratio (ER, ratio between the anatomical dose and the corresponding ground level dose) for each body site without requiring individual measurements. A 3D numeric model (SimUVEx) was used to compute ER for various body sites and postures. A multiple fractional polynomial regression analysis was performed to identify predictors of ER. The regression model used simulation data and its performance was tested on an independent data set. Two input variables were sufficient to explain ER: the cosine of the maximal daily solar zenith angle and the fraction of the sky visible from the body site. The regression model was in good agreement with the simulated data ER (R2=0.988). Relative errors up to +20% and −10% were found in daily doses predictions, whereas an average relative error of only 2.4% (−0.03% to 5.4%) was found in yearly dose predictions. The regression model predicts accurately ER and UV doses on the basis of readily available data such as global UV erythemal irradiance measured at ground surface stations or inferred from satellite information. It renders the development of exposure data on a wide temporal and geographical scale possible and opens broad perspectives for epidemiological studies and skin cancer prevention.

Sweetened carbonated beverage consumption and cancer risk: meta-analysis and review.

There is speculation on an association between sweetened, carbonated beverage consumption and cancer risk. This study aimed to examine this issue. Over 50 independent estimates of risk were available, 11 for colas specifically. A random-effects meta-analysis was carried out with tests for publication bias performed as well as Higgins and Thompson’s I2 measure of the percentage of heterogeneity between studies that could not be explained by chance. Over all the different sites of cancer, the summary relative risk (SRR), when all 55 independent estimates were considered together, was SRR=1.03 [95% confidence interval (0.96; 1.11)]. When individual cancer sites were considered, there was no significant increase or decrease in the meta-analysis estimate of risk of cancer of the pancreas, bladder, kidney, squamous cell or adenocarcinoma of the oesophagus, colon, gastric cardia, gastric noncardia, prostate, breast, larynx and ovary or of the oral cavity, pharynx or glioma. There was no evidence in a sensitivity analysis from those studies that reported results separately for colas of an associated risk of pancreas cancer [SRR=1.00, 95% confidence interval (0.61; 1.65)]. The results for all other forms of cancers were considerably hampered by poor methodology and small numbers of studies (mainly one report on each cancer site studied). Overall, the findings are reassuring in terms of the association between soft drinks, including colas, and cancer risk, although the quality of many of the studies is quite poor by acceptable, modern standards and no study has been carried out with use of carbonated beverages as a primary hypothesis.