Case-control Study In France Research Articles

SARS-CoV-2 incubation period across variants of concern, individual factors, and circumstances of infection in France: a case series analysis from the ComCor study

The incubation period of SARS-CoV-2 has been estimated for the known variants of concern. However, differences in study designs and settings make comparing variants difficult. We aimed to estimate the incubation period for each variant of concern compared with the historical strain within a unique and large study to identify individual factors and circumstances associated with its duration. In this case series analysis, we included participants (aged ≥18 years) of the ComCor case-control study in France who had a SARS-CoV-2 diagnosis between Oct 27, 2020, and Feb 4, 2022. Eligible participants were those who had the historical strain or a variant of concern during a single encounter with a known index case who was symptomatic and for whom the incubation period could be established, those who reported doing a reverse-transcription-PCR (RT-PCR) test, and those who were symptomatic by study completion. Sociodemographic and clinical characteristics, exposure information, circumstances of infection, and COVID-19 vaccination details were obtained via an online questionnaire, and variants were established through variant typing after RT-PCR testing or by matching the time that a positive test was reported with the predominance of a specific variant. We used multivariable linear regression to identify factors associated with the duration of the incubation period (defined as the number of days from contact with the index case to symptom onset). 20 413 participants were eligible for inclusion in this study. Mean incubation period varied across variants: 4·96 days (95% CI 4·90-5·02) for alpha (B.1.1.7), 5·18 days (4·93-5·43) for beta (B.1.351) and gamma (P.1), 4·43 days (4·36-4·49) for delta (B.1.617.2), and 3·61 days (3·55-3·68) for omicron (B.1.1.529) compared with 4·61 days (4·56-4·66) for the historical strain. Participants with omicron had a shorter incubation period than participants with the historical strain (-0·9 days, 95% CI -1·0 to -0·7). The incubation period increased with age (participants aged ≥70 years had an incubation period 0·4 days [0·2 to 0·6] longer than participants aged 18-29 years), in female participants (by 0·1 days, 0·0 to 0·2), and in those who wore a mask during contact with the index case (by 0·2 days, 0·1 to 0·4), and was reduced in those for whom the index case was symptomatic (-0·1 days, -0·2 to -0·1). These data were robust to sensitivity analyses correcting for an over-reporting of incubation periods of 7 days. SARS-CoV-2 incubation period is notably reduced in omicron cases compared with all other variants of concern, in young people, after transmission from a symptomatic index case, after transmission to a maskless secondary case, and (to a lesser extent) in men. These findings can inform future COVID-19 contact-tracing strategies and modelling. Institut Pasteur, the French National Agency for AIDS Research-Emerging Infectious Diseases, Fondation de France, the INCEPTION project, and the Integrative Biology of Emerging Infectious Diseases project.

Sleep Traits, Night Shift Work and Lung Cancer Risk among Women: Results from a Population-Based Case-Control Study in France (The WELCA Study).

Circadian rhythm disruption due to night shift work and/or sleep disorders is associated with negative health outcomes including cancer. There is only scant evidence of an association with lung cancer, unlike breast and prostate cancer. We explore the role of sleep disorders and night shift work in lung cancer risk among women in a population-based case-control study, including 716 lung cancer cases and 758 controls. Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) associated with sleep duration per day (<7 h, 7−7.9 h, ≥8 h), a summary index of sleep disorders, chronotype, and night shift work exposure metrics. When compared to women with an average sleep duration of 7−7.9 h per day, the OR was 1.39 (95% CI 1.04−1.86) in long sleepers (≥8 h) and 1.16 (95% CI 0.86−1.56) in short sleepers (<7 h). Overall, lung cancer was not associated with the sleep disorder index, nor with night shift work, regardless of the duration of night work or the frequency of night shifts. However, elevated OR associated with the sleep disorder index were found in the subgroup of current smokers. The U-shaped association of lung cancer with sleep duration was more particularly pronounced among women who worked at night ≥5 years. Our findings suggested that sleep patterns are associated with lung cancer risk in women with a potential modifying effect by night shift work duration or tobacco smoking.

Sleep Patterns and Risk of Prostate Cancer: A Population-Based Case Control Study in France (EPICAP).

Sleep disturbances have been singled out for their implication in the risk of several cancer sites. However, results for prostate cancer are still inconsistent. We used data from the EPICAP study, a French population-based case-control study including 819 incident prostate cancer cases and 879 controls frequency matched by age. Detailed information on sleep duration on work/free days, and sleep medication over lifetime was collected. Sleep duration and sleep deprivation were not associated with prostate cancer, whatever the aggressiveness of prostate cancer. However, sleep deprivation was associated with an increased prostate cancer risk among men with an evening chronotype [OR, 1.96; 95% confidence interval (CI), 1.04-3.70]. We also observed an increased risk of prostate cancer with higher duration of sleep medication use (Ptrend = 0.008). This association with long duration of sleep medication use (≥10 years) was more pronounced among men who worked at night 15 years or more (OR, 3.84; 95% CI, 1.30-11.4) and among nonusers of NSAID (OR, 2.08; 95% CI, 1.15-3.75). Our results suggested that chronotype, night work, or NSAID use could modify the association between sleep disorders and prostate cancer occurrence needing further investigations to go further. EPICAP is the first study, which investigates several sleep indicators taking into account potential effect modifiers. If our findings were confirmed, we could identify subgroups of men at higher risk of prostate cancer that may be accessible to preventive measures.

Preliminary study of the social withdrawal (hikikomori) spectrum in French adolescents: focusing on the differences in pathology and related factors compared with Japanese adolescents

BackgroundSocial withdrawal (hikikomori) has become an internationally recognized phenomenon, but its pathology and related factors are not yet fully known. We previously conducted a statistical case-control study on adolescent patients with hikikomori in Japan, which revealed the non-specificity of pathology in patients with hikikomori. Further, environmental factors, such as the lack of communication between parents and Internet overuse, were found to be significant predictors of hikikomori severity. Here, we aimed to conduct a similar preliminary case-control study in France and to compare the results with those from the study conducted in Japan.MethodsParents of middle school students who underwent psychiatric outpatient treatment for hikikomori (n = 10) and control group parents (n = 115) completed the Child Behavior Checklist to evaluate their child’s psychopathological characteristics and the Parental Assessment of Environment and Hikikomori Severity Scales, as in our previous study in Japan. We compared the descriptive statistics and intergroup differences in France with those from the previous study conducted in Japan. In the multiple regression analysis to find predictors of hikikomori severity in French and also Japanese subjects, the same dependent and independent variables were chosen for the present study (both differed from the previous study). These were used in order to make accurate intercountry comparisons.ResultsThe comparisons revealed no differences in the pathology of hikikomori between Japan and France. Specifically, both studies found similarly increased scores for all symptom scales, with no specific bias. However, the statistical predictors of hikikomori severity in France (lack of communication between parents and child and lack of communication with the community) differed from those in Japan (lack of communication between parents).ConclusionHikikomori in Japan and France could be considered essentially the same phenomenon; moreover, our findings demonstrated the universal non-specificity and unbiasedness of the hikikomori pathology. This suggests that hikikomori is not a single clinical category with a specific psychopathology; instead, it is a common phenotype with various underlying pathologies. However, different strategies may be required in each country to prevent the onset and progression of hikikomori.

A Comparative Study of Adolescent Social Withdrawal (Hikikomori) in Japan and France

IntroductionPreviously, we conducted a statistical case-control study of adolescent Hikikomori patients in Japan using the Parental Assessment of Psychological, Behavioral and Environment Scales. That study did not reveal any pathologies specific to Hikikomori patients. On the other hand, environmental factors such as “lack of communication between parents” and “overuse of the Internet” were shown to be significant predictors of Hikikomori severity.ObjectivesIn this study, using the same methodology as our previous study in Japan, we conducted a case-control study in France. The following questions were examined : (1) whether the pathology of Hikikomori patients in Japan and France is the same, and (2) whether the environmental factors associated with the severity of Hikikomori are the same in Japan and France.MethodsUsing CBCL and our original scales, we descriptive-statistically compared clinical and subclinical psycho-behavioral characteristics of adolescent Hikikomori patients and a control group. In addition, environmental factors that make Hikikomori more severe were clarified by multiple regression analysis.ResultsThe results showed that there was no difference in the pathology of Hikikomori between Japan and France. On the other hand, the statistical predictors of Hikikomori severity were “lack of communication between parents and children” and “Lack of communication with the community,” which differed from those in Japan.ConclusionsAlthough it is safe to assume that Japanese and French Hikikomori’s pathology is generally the same, different strategies may be needed to prevent the onset of Hikikomori and to stop it from becoming severe.DisclosureNo significant relationships.

Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France.

SummaryBackgroundWe aimed to assess the settings and activities associated with SARS-CoV-2 infection in the context of B.1.617.2 (Delta) variant circulation in France, as well as the protection against symptomatic Delta infection.MethodsIn this nationwide case-control study, cases were SARS-CoV-2 infected adults recruited between 23 May and 13 August 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire and multivariable logistic regression analysis was used to determine the association between acute SARS-CoV-2 infection and recent activity-related exposures, past history of SARS-CoV-2 infection, and COVID-19 vaccination.FindingsWe did not find any differences in the settings and activities associated with Delta versus non-Delta infections and grouped them for subsequent analyses. In multivariable analysis involving 12634 cases (8644 Delta and 3990 non-Delta) and 5560 controls, we found individuals under 40 years and attending bars (aOR:1.9; 95%CI:1.6-2.2) or parties (aOR:3.4; 95%CI:2.8-4.2) to be at increased risk of infection. In those aged 40 years and older, having children attend daycare (aOR:1.9; 95%CI:1.1-3.3), kindergarten (aOR:1.6; 95%CI:1.2-2.1), primary school (aOR:1.4; 95%CI:1.2-1.6) or middle school (aOR:1.3; 95%CI:1.2-1.6) were associated with increased risk of infection. We found strong protection against symptomatic Delta infection for those with prior infection whether it was recent (2-6 months) (95%; 95%CI:90-97) or associated with one dose (85%; 95%CI:78-90) or two doses of mRNA vaccine (96%; 95%CI:87-99). For those without past infection, protection was lower with two doses of mRNA vaccine (67%; 95%CI:63-71).InterpretationIn line with other observational studies, we find reduced vaccine effectiveness against symptomatic Delta infections. The settings and activities at increased risk of infection indicate where efforts to reinforce individual and public health measures need to be concentrated.

Impact of original, B.1.1.7, and B.1.351/P.1 SARS-CoV-2 lineages on vaccine effectiveness of two doses of COVID-19 mRNA vaccines: Results from a nationwide case-control study in France.

BackgroundWe aimed to assess the effectiveness of two doses of mRNA COVID-19 vaccines against COVID-19 with the original virus and other lineages circulating in France.MethodsIn this nationwide case-control study, cases were SARS-CoV-2 infected adults with onset of symptoms between 14 February and 3 May 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire on recent activity-related exposures and vaccination history. Information about the infecting virus was based on a screening RT-PCR for either B.1.1.7 or B.1.351/P.1 variants.FindingsIncluded in our analysis were 7 288 adults infected with the original SARS-CoV-2 virus, 31 313 with the B.1.1.7 lineage, 2 550 with B.1.351/P1 lineages, and 3 644 controls. In multivariable analysis, the vaccine effectiveness (95% confidence interval) seven days after the second dose of mRNA vaccine was estimated at 88% (81-92), 86% (81-90) and 77% (63-86) against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively. Recent (2 to 6 months) history of virologically confirmed SARS-CoV-2 infection was found to be 83% (76-88), 88% (85-91) and 83% (71-90) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively; and more distant (> 6 months) infections were 76% (54-87), 84% (75-90), and 74% (41-89) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively.InterpretationIn real-life settings, two doses of mRNA vaccines proved to be effective against COVID-19 with the original virus, B.1.1.7 lineage and B.1.351/P.1 lineages.FundingInstitut Pasteur, Research & Action Emerging Infectious Diseases (REACTing), Fondation de France (Alliance “Tous unis contre le virus”).

Risk of lung cancer among women in relation to lifetime history of tobacco smoking: a population-based case-control study in France (the WELCA study)

BackgroundThis study aims to provide new insights on the role of smoking patterns and cigarette dependence in female lung cancer, and to examine differences by histological subtype.MethodsWe conducted a population-based case-control study in the great Paris area among women including 716 incident cases diagnosed between 2014 and 2017 and 757 age-matched controls. Detailed data on smoking history was collected during in-person interviews to assess intensity and duration of tobacco smoking, time since cessation, smoking habits (depth of smoke inhalation, use of filter, type of tobacco, and type of cigarettes) and Fagerström test for cigarette dependence. The comprehensive smoking index (CSI), a score modelling the combined effects of intensity, duration and time since quitting smoking was determined for each subject. Multivariable logistic regression models were fitted to calculate odds ratios (ORs) and their confidence intervals (95%CI) of lung cancer associated with smoking variables.ResultsLung cancer risk increased linearly with intensity and duration of tobacco smoking while it decreased with time since cessation, to reach the risk in never-smokers after 20 years of abstinence. The combined effect of intensity and duration of tobacco smoking was more than multiplicative (p-interaction 0.012). The OR in the highest vs the lowest quartile of CSI was 12.64 (95%CI 8.50; 18.80) (p-trend < 0.001). The risk of small cell or squamous cell carcinomas increased with the CSI more sharply than the risk of adenocarcinomas. Deep smoke inhalation, dark vs blond tobacco, conventional vs light cigarettes, and unfiltered vs filtered cigarettes, as well as having mixed smoking habits, were found to be independent risk factors. Having high cigarette addiction behaviours also increased the risk after adjusting for CSI.ConclusionThis study provides additional insights on the effects of tobacco smoking patterns on lung cancer risk among women.

Delivery Hospital Characteristics and Postpartum Maternal Mortality: A National Case-Control Study in France

(Anesth Analg. 2020;130:52–62) While obstetric care providers are always focused on ensuring the best outcomes for their patients, not much empirical evidence is available to illustrate how a hospital’s organizational structure can affect maternal and neonatal outcomes. Research has shown that premature infants who are transferred to specialty centers experience better health outcomes, but there is variability in how facilities classify maternal risk factors that would indicate a need for preterm delivery. This inconsistency in procedure presents a number of maternal health risks, and so Saucedo and colleagues conducted their study to determine how a hospital’s organizational characteristics affect the risk of postpartum maternal death.

Association of characteristics of tampon use with menstrual toxic shock syndrome in France

SummaryBackgroundMenstrual tampons are widely used in western countries. Indirect evidence suggests that tampon misuse could be associated with an increased risk of menstrual toxic shock syndrome (MTSS). The aim of this study was to determine what characteristics of tampon use are associated with increased risk of menstrual toxic shock syndrome (MTSS).MethodsA nationwide, case-control study in France, was conducted with women that use tampons with MTSS diagnoses according to the CDC diagnostic criteria (n = 55, from January 2011, to December 2017) and a control group of women with no MTSS history (n = 126, from February to December 2017). Information regarding tampon use during a 6-month period was collected. Associations between tampon use and MTSS were assessed using logistic regression models stratified by residential area.FindingsCompared to controls, women diagnosed with MTSS more frequently reported maximum tampon wear of >6 h (62% vs. 41%; P = 0.02), overnight tampon use (77% vs. 54%; P = 0.006), and neither read nor followed tampon instructions in case of reading (65% vs. 42%; P = 0.006). In univariate analysis, MTSS risk was two-fold higher with tampon use for >6 consecutive hours (odds ratio, 2.3 [95% CI, 1.2–4.5]), and three-fold higher with tampon use during sleep for >8 h (odds ratio, 3.2 [95% CI, 1.4–7.7]). In multivariate logistic regression analysis, only maximum tampon use for >6 h (odds ratio, 2.03 [95% CI, 1.04–3.98]), and neither read nor followed the tampon instructions in case of reading (odds ratio, 2.25 [95% CI, 1.15–4.39]) were independently associated with MTSS.InterpretationOur study suggests that the risk of MTSS was associated with using tampons for more than 6 h, overnight tampon use during sleep, and neither read nor followed tampon insertion instructions in case of reading.FundingLABEX ECOFECT (ANR-11-LABX-0048) of Université de Lyon within the programme “Investissements d'Avenir” (ANR-11-IDEX-0007) operated by the French National Research Agency (ANR).

Association of Characteristics of Tampon Use with Menstrual Toxic Shock Syndrome in France

Background: Menstrual tampons are widely used in western countries. Indirect evidence suggests that tampon misuse could be associated with an increased risk of menstrual toxic shock syndrome (MTSS). The aim of the study was to determine tampon use associated with increased risk of menstrual toxic shock syndrome (MTSS). Methods: A nationwide, case-control study in France, was conducted with women that use tampon with MTSS diagnoses according to the CDC diagnostic criteria (n=55, from January 2011, to December 2017) and controls women with no MTSS history (n=126, from February to December 2017). Information regarding tampon use during a 6-month period was collected. Associations between tampon use and MTSS were assessed using logistic regression models stratified by residential area. Findings: Compared to controls, cases more frequently reported maximum tampon wear of >6 hours (62% vs. 41%; P=0.02), overnight tampon use (77% vs. 54%; P=0.006), and not having read and followed tampon instructions (65% vs. 42%; P=0.006). In univariate analysis, MTSS risk was two-fold higher with tampon use for >6 consecutive hours (odds ratio, 2.3 [95% CI, 1.2–4.5]), and three-fold higher with tampon use during sleep for >8 hours (odds ratio, 3.2 [95% CI, 1.4–7.7]). In multivariate logistic regression analysis, only maximum tampon use for >6 hours (odds ratio, 2.03 [95% CI, 1.04–3.98]), and not reading and following the tampon instructions (odds ratio, 2.25 [95% CI, 1.15–4.39]) were independent associated with MTSS. Interpretation: Our study indicates suggests that risk of MTSS was associated with women who used tampons for more than 6 hours, overnight tampon during sleep, and who reported not reading and following tampon insertion instructions. Funding Statement: This work was supported by the LABEX ECOFECT (ANR-11-LABX-0048) of Universite de Lyon within the programme Investissements d'Avenir (ANR-11-IDEX-0007) operated by the French National Research Agency (ANR). Declaration of Interests: The authors declare no competing interest. Ethics Approval Statement: This study was reviewed and accepted by the Ethics Committee (CPP Sud Est IV, Centre Leon Berard, Lyon, France, N° L16-176). Written consent was obtained from all participants, or from the parents/guardians of participants under 18 years of age.

Occupational exposure to petroleum-based and oxygenated solvents and oral and oropharyngeal cancer risk in men: A population-based case-control study in France

ObjectiveTo examine the association between occupational exposure to petroleum-based and oxygenated solvents and the risk of oral and oropharyngeal cancer. MethodsThe ICARE study is a large population-based case-control study conducted in France between 2001 and 2007. This present analysis was restricted to men and included 350 and 543 cases of squamous cell-carcinoma of the oral cavity and oropharynx, respectively, and 2780 controls. Lifetime tobacco, alcohol consumption and complete occupational history were assessed through detailed questionnaires. Job-exposure matrices allowed us to assess occupational exposure to five petroleum-based solvents (white spirits; diesel/fuel oils/kerosene; gasoline; benzene; special petroleum products) and five oxygenated solvents (diethyl ether; tetrahydrofuran; ketones and esters; alcohols; ethylene glycol). Odds-ratios (ORs), adjusted for age, smoking, alcohol consumption and socioeconomic status, and 95% confidence intervals (CI) were estimated using unconditional logistic models. ResultsAssociations between oral cancer risk and exposure to white spirits and diesel/fuel oils/kerosene were suggested, but there was no exposure-response trend. Concerning exposure to oxygenated solvents, participants with the highest levels of cumulative exposure to diethyl ether had a significant excess risk of oropharyngeal cancer (OR = 7.78, 95%CI 1.42 to 42.59; p for trend = 0.04). Ever exposure to tetrahydrofuran was associated with a borderline significant increased risk of oral cancer (OR = 1.87, 95%CI 0.97 to 3.61), but no exposure-response trend was observed. Additional adjustments for exposure to other solvents did not substantially change the results. ConclusionOur results do not provide evidence for a major role of petroleum-based and oxygenated solvents in the occurrence of oral and oropharyngeal cancers in men.

Occupational exposure to organic solvents and risk of breast cancer: Results of the CECILE study, a population-based case-control study in France

Introduction Breast cancer is the leading cause of cancer death in women worldwide. Its incidence is only partially explained by well-established risk factors related to hormones and reproduction. It has been suggested that exposure to organic solvents in the workplace may play a role in the etiology of breast cancer, but epidemiological studies on these occupational exposures in female breast cancer did not assess exposure to specific solvents and reported inconsistent results. Methods We examined the risk of breast cancer-related to lifetime exposure to organic solvents in a large population-based case-control study carried out in France between 2005 and 2008; 1230 women newly diagnosed for a breast cancer and 1315 population controls were included. A standardized questionnaire was administered during in-person interviews by trained interviewers to obtain information on socio-demographic characteristics, medical and family history, anthropometric measurements, reproductive history, tobacco and alcohol consumption, diet, and lifetime occupational history. All jobs held during occupational history were coded using the International Standard Classification of Occupations (ISCO 1968) and the Classification of Activities in the European Community (NACE 1991). Exposure to chlorinated (n = 4), petroleum (n = 5) and oxygenated (n = 5) solvents was assessed using a detailed job-exposure matrix (JEM) developed by the French National Agency for Public Health. Each job held was assigned indices of exposure probability, frequency and intensity. A Cumulative Exposure Score (CES) was calculated for each subject as the sum of the products of exposure probability, frequency and intensity, and duration for each job held over the entire occupational life. Odds ratio (ORs) and their 95% confidence intervals (95% CI) were estimated using unconditional logistic regression adjusting for potential confounders. Results The highest lifetime exposure prevalence was found for alcoholic solvents (41.8% of the cases and 41.4% of the controls); white spirit (8.3% of the cases and 10.2% of the controls); and trichloroethylene (10.7% of the cases and 11.8% of the controls). Compared to non-exposed subjects, women in the highest cumulative exposure quartile for alcoholic solvents had an OR of 1.17 (95% CI = 0.90–1.52). This OR increased to 1.61 (95% CI = 1.06–2.46) in premenopausal women. Exposure to ethylene glycol was also associated with an increased OR of 1.36 (95% CI = 0.93–1.97) in premenopausal women. No association was observed for other oxygenated solvents, petroleum solvents or chlorinated solvents. Conclusions These findings suggest a role of occupational exposure to oxygenated solvents, notably to alcohols, in the occurrence of breast cancer. Further studies conducted in cohorts of women with high prevalence of exposure to solvents are needed to confirm these results.

Selective COX2 inhibitors, other NSAIDS, and influence of COX2 polymorphisms on breast cancer risk: Results from the CECILE study

Background In the context of a possible role of chronic inflammation in cancer risk, our objective was to investigate breast cancer risk in relation to the use of selective COX2 inhibitors and other non-steroidal anti-inflammatory drugs (NSAIDs) including aspirin, and to explore interactions of NSAIDs with COX2 genetic polymorphisms. Methods We conducted a population-based case-control study in France on breast cancer risk factors. Data on NSAID use were obtained in 871 cases and 915 controls using a standardized questionnaire, and 7 single nucleotide polymorphisms in the COX2 gene were genotyped in 811 cases and 829 controls. Odds ratios (OR) and their 95% confidence intervals (CI) were calculated using unconditional logistic regression models. Results We found an inverse association between breast cancer and NSAID use (OR = 0.80, 95% CI: 0.66–0.97), which was stronger for COX2 selective inhibitors (OR = 0.55, 95% CI: 0.35–0.86). Associations were more pronounced in salicylate non-users and overweight women. The SNP rs5275 in COX2 genes was associated with breast cancer (P = 0.01) and a significant interaction between rs5275 and NSAID use was observed (P for interaction 0.02). Conclusion Our results confirm an inverse association between NSAID use and breast cancer and highlight the role of selective COX2 inhibitors. Polymorphisms of the COX2 gene may modify the risk of breast cancer associated with NSAID use.

Occupational exposure to chlorinated solvents and risk of head and neck cancer in men: a population-based case-control study in France

BackgroundFew epidemiological studies have investigated the link between occupational exposure to solvents and head and neck cancer risk, and available findings are sparse and inconsistent. The objective of this study was to examine the association between occupational exposure to chlorinated solvents and head and neck cancer risk.MethodsWe analyzed data from 4637 men (1857 cases and 2780 controls) included in a population-based case-control study, ICARE (France). Occupational exposure to five chlorinated solvents (perchloroethylene [PCE], trichloroethylene [TCE], methylene chloride [MC], chloroform [CF], and carbon tetrachloride [CT]) was assessed through job-exposure matrices. Odds ratios (ORs) and confidence intervals (95% CI) were estimated by unconditional logistic regression, adjusted for age, tobacco smoking, alcohol consumption, asbestos exposure, and other potential confounders.ResultsWe observed no association between chlorinated solvent exposure and head and neck cancer risk, despite a non-significant increase in risk among subjects who had the highest cumulative level of exposure to PCE, (OR = 1.81; 95% CI = 0.68 to 4.82). In subsite analysis, the risk of laryngeal cancer increased with cumulative exposure to PCE (p for trend = 0.04). The OR was 3.86 (95% CI = 1.30 to 11.48) for those exposed to the highest levels of PCE. A non-significant elevated risk of hypopharyngeal cancer was also observed in subjects exposed to the highest levels of MC (OR = 2.36; 95% CI = 0.98 to 5.85).ConclusionOur findings provide evidence that high exposure to PCE increases the risk of laryngeal cancer, and suggest an association between exposure to MC and hypopharyngeal cancer. Exposure to other chlorinated solvents was not associated with the risk of head and neck cancer.

Hormonal and reproductive risk factors of papillary thyroid cancer: A population-based case-control study in France

The three times higher incidence of thyroid cancer in women compared to men points to a role of female sex hormones in its etiology. However the effects of these factors are poorly understood. We analyzed the association between thyroid cancer and hormonal and reproductive factors among women enrolled in CATHY, a population-based case-control study conducted in France. The study included 430 cases of papillary thyroid cancer and 505 controls frequency-matched on age and area of residence. The odds ratios for thyroid cancer increased with age at menarche (p trend 0.05). Postmenopausal women were at increased risk, as compared to premenopausal women, particularly if menopause followed an ovariectomy, and for women with age at menopause <55years. In addition, use of oral contraceptives and menopausal hormone therapy reduced the association with thyroid cancer by about one third, and breastfeeding by 27%. Overall, these findings provide evidence that the risk of thyroid cancer increases with later age at menarche and after menopause, and decreases with use of oral contraceptives and menopausal hormone therapy. These findings confirm an implication of hormonal factors in papillary thyroid cancer risk, whose mechanisms need to be elucidated.

Weight and weight changes throughout life and postmenopausal breast cancer risk: a case-control study in France.

BackgroundOverweight and weight gain throughout adult life have been associated with increased risk of breast cancer after the menopause. However the role of body weight at a young age and of the timing of weight gain over the lifetime in postmenopausal breast cancer is not well documented.MethodsWe conducted a population-based case-control study on breast cancer in France that included 739 cases and 815 population controls in postmenopausal women. Height, weight at age 20, 40 and 50 as well as weight one year before diagnosis were obtained during in-person interviews.ResultsNo association between body mass index at the age of 20 years and breast cancer after the menopause was detected. However, we found that postmenopausal breast cancer was associated with weight gain between ages 40 and 50 years (OR per 5 kg/m2 increase in BMI: 1.45 [95%ci 1.06−1.98]). The increased risk of breast cancer associated with weight gain was more consistent in leaner women at age 20, in older postmenopausal women (>65 years), and in women who did not use menopausal hormone therapy.ConclusionsThese findings point to the importance of controlling for weight gain in middle aged-women. The role of low body weight in young adulthood in breast cancer risk after the menopause should be further scrutinized.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2793-0) contains supplementary material, which is available to authorized users.

Risk of Breast Cancer by Type of Menopausal Hormone Therapy: a Case-Control Study among Post-Menopausal Women in France

BackgroundThere is extensive epidemiological evidence that menopausal hormone therapy (MHT) increases breast cancer risk, particularly combinations of estrogen and progestagen (EP). We investigated the effects of the specific formulations and types of therapies used by French women. Progestagen constituents, regimen (continuous or sequential treatment by the progestagen), and time interval between onset of menopause and start of MHT were examined.MethodsWe conducted a population-based case-control study in France in 1555 menopausal women (739 cases and 816 controls). Detailed information on MHT use was obtained during in-person interviews. Odds ratios and 95% confidence interval adjusted for breast cancer risk factors were calculated.ResultsWe found that breast cancer risk differed by type of progestagen among current users of EP therapies. No increased risk was apparent among EP therapy users treated with natural micronized progesterone. Among users of EP therapy containing a synthetic progestin, the odds ratio was 1.57 (0.99-2.49) for progesterone-derived and 3.35 (1.07-10.4) for testosterone-derived progestagen. Women with continuous regimen were at greater risk than women treated sequentially, but regimen and type of progestagen could not be investigated independently, as almost all EP combinations containing a testosterone-derivative were administered continuously and vice-versa. Tibolone was also associated with an increased risk of breast cancer. Early users of MHT after onset of menopause were at greater risk than users who delayed treatment.ConclusionThis study confirms differential effects on breast cancer risk of progestagens and regimens specifically used in France. Formulation of EP therapies containing natural progesterone, frequently prescribed in France, was not associated with increased risk of breast cancer but may poorly protect against endometrial cancer.

Night work and breast cancer: A population‐based case–control study in France (the CECILE study)

Night work involving disruption of circadian rhythm was suggested as a possible cause of breast cancer. We examined the role of night work in a large population-based case-control study carried out in France between 2005 and 2008. Lifetime occupational history including work schedules of each night work period was elicited in 1,232 cases of breast cancer and 1,317 population controls. Thirteen percent of the cases and 11% of the controls had ever worked on night shifts (OR = 1.27 [95% confidence interval = 0.99-1.64]). Odds ratios were 1.35 [1.01-1.80] in women who worked on overnight shifts, 1.40 [1.01-1.92] in women who had worked at night for 4.5 or more years, and 1.43 [1.01-2.03] in those who worked less than three nights per week on average. The odds ratio was 1.95 [1.13-3.35] in women employed in night work for >4 years before their first full-term pregnancy, a period where mammary gland cells are incompletely differentiated and possibly more susceptible to circadian disruption effects. Our results support the hypothesis that night work plays a role in breast cancer, particularly in women who started working at night before first full-term pregnancy.

Abstract 655: Menopausal hormone therapy and breast cancer risk: The CECILE Study

Abstract Breast cancer in post-menopausal women has been associated with the use of menopausal hormone therapy (MHT). Estrogen-only (EO) and combined estrogen-progestagen (EP) therapies have been evaluated as potentially carcinogenic to human by the IARC. However, the type of estrogen and progestagen in the MHT varies considerably by country. For example, besides synthetic progestagens, the use of natural progesterone in combined EP therapy is specific to France. We investigated whether the association between MHT and breast cancer in postmenopausal women differ by type of chemical compound. We conducted a population-based case-control study in France in 762 cases and 840 controls recruited among postmenopausal women in two French “départements”. Data were collected including name of medication, date of start and end of each medication used. Unconditional logistic regression models were used, with adjustment for age, study area, and known risk factors for breast cancer. We observed a significant increased risk of breast cancer for current users of estrogen plus synthetic progestagen while no association was found for any use of estrogen-only therapy or combined therapy of estrogen plus natural progesterone. Among current users of estrogen plus synthetic progestagen, the association with breast cancer increased with duration of use and was higher in women who started their treatment before or shortly after menopause. Our study suggests that the use of natural progesterone as the progestagen component in a combined EP therapy is not associated with an increased risk of breast cancer. This result reinforces the findings reported in another cohort study of French women (E3N). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 655. doi:1538-7445.AM2012-655