[Large health cohorts in France]. / Les grandes cohortes en santé en France.

A cohort is composed of a group of individuals sharing a number of features and who are monitored longitudinally, at the individual level, according to a pre-established protocol. Since 2008, funding of health cohorts in France by Trés Grandes Infrastructures de Recherche (Very Large Research Infrastructures, TGIR) and associated public stimulus investments has led to the creation of 15 very large cohorts involving either the general population or patients with particular diseases. As platforms for research in life sciences and health, these cohorts, funded for ten years, will develop shareable databases. Many health issues, especially biological, medical, social and environmental disease determinants and their interactions, will benefit from innovative approaches. Parallel constitution of biobanks and the use of new technologies for communication, data sharing and international cooperation will reinforce this initiative. A new longitudinal and systematic approach is strengthening the research infrastructure.

When do involuntarily infertile couples choose to seek medical help?

OBJECTIVE: To estimate the probability of medical consultation for infertility during the course of a pregnancy attempt and to study its determinants. DESIGN: Pregnancy-based retrospective telephone survey analyzed with a discrete time Cox model. SETTING: Two rural counties in Brittany and Normandy, France. PATIENT(S): A random sample of 901 women from the general population aged 18-60 years reporting 1,460 pregnancy attempts resulting in a live birth between 1985 and 2000 (participation rate, 73%). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Probability of medical consultation for involuntary infertility cumulated over time. RESULT(S): The cumulative probability of medical consultation for involuntary infertility among nulligravid women was 45% after 12 months of involuntary infertility and 75% after 24 months. The probability of medical consultation at any time was half that for parous women (odds ratio 0.4, 95% confidence interval 0.2-0.6). More highly educated women were more likely to have sought medical help for infertility. Only 45% of women who had sought medical advice received infertility treatment. CONCLUSION(S): Our survival approach provides a description of infertility service use during the course of a pregnancy attempt, and confirms that parity and educational level are strong predictors of medical help-seeking behaviors.

The burden of road traffic accidents in a French Departement: the description of the injuries and recent changes.

BACKGROUND: A significant reduction in road traffic accidents has been observed since prevention measures were introduced by the French public authorities in 2002. The goals of this study are to describe the burden of road traffic accidents in a French Departement, and to identify changes if any between the periods 1997-2001 and 2002-2006 on the basis of the disability adjusted life years (DALY). METHODS: Years of lost life (YLL) and years lived with disability (YLD) were calculated for two periods using the mortality and incidence data in the Rhone Departement Registry of Road Traffic Accident Casualties. RESULTS: YLD and YLL that are related to road traffic accidents are at their maximum value between 15 and 24 years of age. For men, intracranial fractures and intracranial injuries dominate, and for women it is spinal cord injuries that account for highest rates of YLD. A reduction in the rates of YLL and YLD has been observed for both genders and all age groups between 1997-2001 and 2002-2006. CONCLUSION: The reduction in DALY between the two periods is explained both by the reduction in the number of fatalities and injuries but also by an increase in the age at which they occur.

[A population health metric for France]. / Intérêt d'un indicateur synthétique pour décrire la santé en France.

Population health metrics have been developed to help to determine public health priorities. Disability-Adjusted Life Years (DALYs) is an index used to express the number of years of good health lost due to a given disorder, based not only on mortality but also on the duration and sequelae. Based on the DALYs index, the leading health disorders in France, regardless of gender, are neuropsychiatric disorders (7.8%) and depression (11.8%).

Sensitivity analysis in summary measure of population health in France.

BACKGROUND: The aim of this study is to provide estimates of the French burden of disease, using the WHO Global Burden of Disease methodology and to perform sensitivity analysis on different set of mortality data. METHODS: The burden of disease is measured by disability-adjusted life years (DALYs) that take into account both mortality and morbidity data. Results were obtained using French mortality data for the years 2000 and 2001 and morbidity data estimated by WHO for France. Sensitivity analyses were conducted using different mortality data sets and various life tables as mortality norms. Calculations were also performed with and without discounting and age-weighting. RESULTS: In France, the annual burden of disease was about 12.4 million DALYs. Depending on the mortality data set and the choice of social values used for calculation, results could be quite different. The use of WHO estimates for mortality resulted in an underestimation of 2.6% of total DALYs with respect to French data. Changes of the mortality norm imply changes in the number of years of life lost (YLLs), whereas the use of discounting and age-weighting mainly modifies the ranking of diseases. CONCLUSION: DALYs constitute a summary measure of population health, which is a powerful tool for the grading of health problems, allowing to compare fatal and non-fatal diseases. Nevertheless, the validity of results obtained depends primarily on the validity of the input data. Collecting morbidity data (mainly incidence) at the national level is hence an important step in order to assess more accurately the specific burden of diseases in France.

Environmental, occupational and familial risks for testicular cancer: a hospital-based case-control study.

Testicular cancer (TC) risk factors remain largely unknown, except for personal history of cryptorchidism and familial history of TC. We conducted a hospital-based case-control study on familial, environmental and occupational conditions in which we compared 229 cases and 800 controls. TC was correlated with cryptorchidism (OR = 3.02; CI: 1.90-4.79), a history of cryptorchidism in relatives (OR = 2.85; CI: 1.70-4.79), and TC (OR = 9.58; CI: 4.01-22.88], prostate cancer (OR = 1.80; CI: 1.08-3.02) and breast cancer (OR = 1.77; CI: 1.20-2.60) in relatives. Living in a rural area or having regular gardening activity (growing fruit or vegetables) was associated with an increased risk of TC (OR = 1.63; CI: 1.16-2.29; OR = 1.84; CI: 1.23-2.75). Regarding occupation, we found a relationship with employment in metal trimming (OR = 1.96; CI: 1.00-3.86), chemical manufacture (OR = 1.88; CI: 1.14-3.10), industrial production of glue (OR = 2.21; CI: 1.15-4.25), and welding (OR = 2.84; CI: 1.51-5.35). In a multivariate model, only a history of cryptorchidism in the men, cryptorchidism in relatives, TC, and breast cancer remained significant. Our findings contribute further evidence to a pattern of TC risk factors, which include the significant weight of personal reproductive history and also of testicular and breast cancer in relatives. By including in a multivariate model variables linked to environmental and occupational exposure and related to familial cancer history, neither living in a rural area nor any occupational exposure appeared to be a potential environmental TC risk factor.

Male gonadal dose of ionizing radiation delivered during X-ray examinations and monthly probability of pregnancy: a population-based retrospective study.

BACKGROUND: Male gonadal exposure to ionizing radiation may disrupt spermatogenesis, but its influence on the fecundity of couples has been rarely studied. We aimed to characterize the influence of male gonadal dose of ionizing radiation delivered during radiodiagnostic on the monthly probability of pregnancy. METHODS: We recruited a random sample of women who retrospectively described 1110 periods of unprotected intercourse beginning between 1985 and 1999 and leading either to a live birth or to no pregnancy; their duration was censored after 13 months. The male partner answered a telephone questionnaire on radiodiagnostic examinations. We assigned a mean gonadal dose to each type of radiodiagnostic examination. We defined male dose for each period of unprotected intercourse as the sum of the gonadal doses of the X-ray examinations experienced between 18 years of age and the date of discontinuation of contraception. Time to pregnancy was analysed using a discrete Cox model with random effect allowing to estimate hazard ratios of pregnancy. RESULTS: After adjustment for female factors likely to influence fecundity, there was no evidence of an association between male dose and the probability of pregnancy (test of homogeneity, p = 0.55). When compared to couples with a male gonadal dose between 0.01 and 0.20 milligrays (n = 321 periods of unprotected intercourse), couples with a gonadal dose above 10 milligrays had a hazard ratio of pregnancy of 1.44 (95% confidence interval, 0.73-2.86, n = 31). CONCLUSION: Our study provides no evidence of a long-term detrimental effect of male gonadal dose of ionizing radiation delivered during radiodiagnostic on the monthly probability of pregnancy during the year following discontinuation of contraceptive use. Classification errors due to the retrospective assessment of male gonadal exposure may have limited the statistical power of our study.

Were less disabled patients the most affected by 2003 heat wave in nursing homes in Paris, France?

OBJECTIVE: To analyse the change of mortality rates (MRs) and their contributing medical factors among nursing home patients during the 2003 heat wave in France. METHODS: A retrospective observational study was conduced in all nursing homes of the Assistance-Publique-Hôpitaux de Paris (AP-HP), the French largest public hospital group. All AP-HP nursing home patients (4,403) who were institutionalized in May, 2003, were concerned. The MRs of patients between three periods (before, during and after the August 2003 heat wave period) were compared according to their demographic characteristics, level of dependence and medical condition. RESULTS: The MR increased from 2.2 per cent persons month (ppm) (1.9-2.4) before heat wave up to 9.2 ppm (8.0-10.4) during heat wave and back to 2.4 ppm (2.2-2.7) after heat wave. MRs before heat wave were higher among highly dependent patients compared to those less dependent [mortality rate ratio (MRR) = 2.66 (1.69-4.21)]. This difference disappeared during the heat wave [MRR = 1.28 (0.91-1.81)] and appeared again after heat wave [MRR = 2.21 (1.52-3.23)]. The same pattern was observed for several medical conditions, such as severe malnutrition or swallowing disorders. CONCLUSION: These results suggest that medical care during heat wave has been directed towards more fragile patients, helping to limit deaths in this group. Less frail patients made the largest contribution to excess mortality during the heat wave. During extreme weather conditions, specific attention should be paid not only to frail persons, but to all the elderly community.

[Prevention in France, 2004: first elements for reflection]. / La prévention en France, 2004: éléments de réflexion.

Prevention has been underdeveloped in the public health arena, at least in France. It is a complex discipline, relying both on strong scientific methodology as well as social and economical considerations, which may be sometimes a source of conflicts.

How would a decline in sperm concentration over time influence the probability of pregnancy?

BACKGROUND: Reports have suggested a decline in sperm concentration during the second half of the 20th century. The effect of this decline on fecundability (the monthly probability of pregnancy) could be detected in principle by a study of time to pregnancy. In practice, the amplitude of this expected effect is not well known and the statistical power of time-to-pregnancy studies to detect it has not been explored. METHODS: We developed a nonparametric model to describe a temporal decline in sperm concentration using data on French semen donors. We then applied this model to 419 Danish couples planning a first pregnancy in 1992, to predict their time to pregnancy as if the pregnancy attempt had begun during earlier decades with higher sperm concentrations. Finally, we used bootstrap simulations to estimate the statistical power of prospective or retrospective studies that compared fecundability (estimated from time to pregnancy) across these time periods. We express the change in fecundability over time as a fecundability ratio (FR), with values less than 1 indicating decreased fecundability. RESULTS: We estimate that the median sperm concentration decreased by 21% from 1977 to 1992 and by 47% from 1947 to 1992. The estimated decline in fecundability with those semen changes was 7% from 1977 to 1992 (FR = 0.93, adjusted) and 15% from 1947 to 1992 (FR = 0.85, adjusted). The total numbers of couples that would be needed in prospective studies of time to pregnancy to detect these changes in fecundability (with a power of 80%) were 12,000 when comparing 1977 to 1992, and 2000 when comparing 1947 to 1992. Retrospective studies of the same size that excluded childless couples had much lower statistical power and were biased toward the null. CONCLUSION: The effect of realistic declines in sperm concentration on time to pregnancy may be observed only with studies that include several thousand couples.

Does male age affect the risk of spontaneous abortion? An approach using semiparametric regression.

Couples in industrialized countries tend to delay attempting to have children, which may lower their chances of livebirth. The authors assessed the association between male age and the risk of spontaneous abortion between weeks 5 and 20 of pregnancy, controlling for female age. They interviewed by telephone a random cross-sectional population of 1,151 French women who had been pregnant between 1985 and 2000 (participation rate, 73%). A total of 12.2% of the 2,414 pregnancies resulted in spontaneous abortion. Semiparametric regression was used to define a discrete time survival model with a random effect taking into account induced abortions, in which female age was coded by a third-degree polynomial. This final model predicted that the risk (rate ratio) of spontaneous abortion was 2.13-fold higher for women age 25 years whose partner was age 35 years or older than for women age 25 years whose partner was younger than age 35 years (95% confidence interval: 1.07, 4.26). No such increased risk of spontaneous abortion with male age was estimated when the woman was age 35 years (rate ratio = 0.61, 95% confidence interval: 0.35, 1.07). Thus, increasing male age could increase the risk of spontaneous abortion when the female partner is less than 30 years of age.