Biomedical subjects

S Lafont

Publications and source records attributed to S Lafont.

At least 19 recordsLinked to original sources

PubMed2007

Cancer mortality in a synthetic spinning plant in Besançon, France.

OBJECTIVES: To assess the mortality of a cohort of workers in a synthetic textile spinning plant and to evaluate the relationship between mortality from lung, liver and bladder cancer and the processes or the products used. METHODS: The study population consisted of male workers present for at least 6 months in the plant from 1968 to 1984. The cohort was followed until 1999. Vital status and the causes of death were determined by consulting national registries. The population of the Franche-Comté region was used for comparison. In total, 17 groups of exposure were assessed by the industrial hygienist, based on the consensus of an expert group that determined the exposure levels of each job to selected occupational hazards. Each worker was assigned to one or several groups, according to his occupational history. Confounding factors could not be assessed. Standardised mortality ratios (SMR) and 95% bilateral confidence intervals were calculated based on an assumed Poisson distribution of the number of cases to compare the plant mortality and the population mortality. Internal analyses were performed with Cox models in order to assess the risks of death related to the various exposures. RESULTS: In the whole cohort, mortality from all malignant neoplasms was lower than expected, but this was not significant. All the estimated SMRs were lower than or close to 1. The "hot -line fitters" (RR = 2.13; n = 9; 1.06 to 4.29) and the "fibre-drawing workers" (RR = 1.83; n = 20;1.09 to 3.07) experienced a statistically significant excess in mortality from lung cancer. A slightly elevated but not significant risk of death related to lung cancer (RR = 1.5; n = 41; 0.8 to 2.7) was observed in the groups with the highest exposure to mineral fibres. A statistically significant increase in cancer deaths was observed for workers with high exposure to dust (higher intensity: RR = 1.42; n = 79; 1.06 to 1.89). CONCLUSION: Some findings, mainly of lung cancer, justify further exploration in other plants in this industry.

Epidemiologic Methods↗

PubMed2005

Road mobility and the risk of road traffic accident as a driver. The impact of medical conditions and life events.

STUDY OBJECTIVE: We conducted a longitudinal investigation of the impact of self-reported life events and medical conditions on changes in road mobility on the wheel between 2000 and 2002 in order to assess whether these changes would affect the risk of road traffic accident (RTA). METHODS: Data are from a cohort of workers and retirees from the French national gas and electricity companies (the Gazel cohort). In the present study, 10,483 participants were included (7843 men aged 51-61 years and 2640 women aged 46-61 years, in 2000). The link between mobility and the risk of RTA was approximated using data on RTA number during lifetime and reported mobility in 2000. We then compared changes in road mobility between 2000 and 2002 resulting from life events and medical conditions reported to have occurred in the year 2001 or changed when compared to year 2000. We also compared road mobilities in 2000 in order to assess any pre-existing differences before life events and medical conditions. This led to estimation of the effect of road mobility changes on the risk of RTA. RESULTS: Changes in road mobility associated with life events and medical conditions were only found among men. These changes in road mobility were minimal. Ensuing changes in the risk of RTA were estimated to be small (odds-ratios ranged from 0.94 to 1.01). The only life events found to be associated with increased road mobility was an important purchase. Hospitalization, serious RTA, and retiring were associated with reduced road mobility. Concerning medical conditions, men who reported cataract, angina pectoris, diabetes, anxiety and stress, sleep disorder, and depression decreased their road mobility. CONCLUSION: We found no or moderate changes in road mobility resulting from life events and medical conditions, suggesting that results from previous published studies that assessed the impact of life events or medical conditions on RTA were not jeopardized by improper adjustment for road mobility.

Accidents, Traffic↗

PubMed2004

[Compliance in HIV infected adults. Study of opportunistic infection prophylaxis with cotrimoxazole in Ivory Coast].

BACKGROUND: The compliance to a daily treatment for illimited duration and the factors that influence it have been rarely studied in sub-Saharian Africa. OBJECTIVE: Describe the compliance to prophylaxis with cotrimoxazole fort (one tablet per day) and its associated factors in patients infected by HIV participating in a clinical trial in Abidjan. METHOD: The tablets packed in individual blisters were provided every month, and the blisters were recuperated the following month. A global compliance ratio (GCR) was established for each patient (empty blisters at the end of the study/follow-up period during the study) and monthly compliance ratio [MCR] (empty blisters during a visit/time lapse since last visit). For each monthly visit foreseen in the protocol, a respect of the appointment ratio (RAR) was described (visits foreseen in the protocol respected that month/visits foreseen in the protocol). The association of GCR with the characteristics on inclusion was studied using logistic regression methods. RESULTS: 530 adults were followed-up for a mean of 10 months. The MCR and the RAR progressed in parallel, decreasing the first 5 months and stabilizing at around 0.80 for the RAR and 0.70 for the MCR. The mean GCR was of 0.77. Three hundred and nine patients (58%) were considered as compliant (0.80<GCR<1). In multivariate analysis, those belonging to the group of compliers were associated with a paid occupation and with a past of tuberculosis, and was not associated with age, gender, level of education, nationality, civil status, number of persons in the home, proximity of a care center, clinical grade or CD4. DISCUSSION: The estimated compliance was correct and stable. The association with a history of tuberculosis suggests that a person having already followed prolonged daily treatment would be more readily compliant to other long term treatments. CONCLUSION: In Africa, cotrimoxazole is initiated long before the stage of antiretroviral treatment. The concern regarding the efficacy of such prophylaxis raises the question of compliance early on in the disease. This prepares the teams that organise the management of such patients to being faced with the problems of compliance to antiretrovirals.

AIDS-Related Opportunistic Infections↗

PubMed2004

[Normative data for the MMSE, the Benton visual retention test, the Isaacs's set test, the digit symbol substitution test and the Zazzo's cancellation task in subjects over the age 70: results from the PAQUID Study].

UNLABELLED: Introduction. The aim of this study was to produce norms for the Mini-Mental State Examination, the Benton visual retention test, Isaacs's set test, the digit symbol substitution test and Zazzo's cancellation task (short 8-line version), in elderly people. METHODS: Data was collected in a representative sample of 1780 subjects aged 70 years and older, followed-up for five years after inclusion in the PAQUID study. Only individuals who did not have characteristics likely to alter their cognitive performance were considered. RESULTS: Descriptive statistics (median, tenth percentile, first and third quartile) were used to define gender-, age- and education-specific norms. CONCLUSIONS: These norms can be used by clinicians to interpret a patient's performance on several widely used cognitive tests according to the scores obtained by individuals of the same age, gender and educational level.

Aged↗

PubMed2004

[Differences between males and females in traffic accident risk in France].

BACKGROUND: In France 7,720 people were killed in traffic accidents in 2001, 75% of which were men; the number of injured people is estimated at 153,945, of which 65% were men. The objective of the study is to describe differences between males and females regarding accidents, and to explain the main reasons for these differences. METHODS: Analysis is conducted from both national police data (2001) and data from the Rhone medical road accident trauma Register (1996-2001). RESULTS: The male/female incidence rate is 3.1 for mortality (95% CI: 3.0-3.3) and 1.7 for morbidity (95% CI: 1.7-1.8). Two-wheel motorised vehicle accidents are very specific to males, which explains part of this overrepresentation. The fatality rate and the severe injuries rate among survivors are higher for males. This is true for every main user group (car users, motorised two-wheelers, cyclists, pedestrians) after adjusting for accident circumstances and age of casualties. Males are more severely injured for all body regions and have more often severe after-effects. CONCLUSIONS: This paper shows the mechanisms leading to this unfavourable outcome for men. They correspond to differences in the number of trips, in the choice of road transport types, and moreover to differences in risk-taking behaviours. Underlying these behaviours, deep-rooted, strong and rather invariant differences between genders are to be found in the values associated with risk-taking on the road.

Accidents, Traffic↗

PubMed2004

Traffic ticket fixing and driving behaviours in a large French working population.

STUDY OBJECTIVE: The use of connections who have the authority to cancel penalties related to traffic violations seems to be very frequent in France. This study aimed at describing risk taking driving behaviours associated in France with using connections to have traffic tickets cancelled (ticket fixing). DESIGN: Retrospective study on driving behaviour and road safety conducted between March and December 2001 within a cohort of French employees. SETTING: France. PARTICIPANTS: Employees of the French national utility company who have been followed up since 1989. The sample comprises 10 594 men aged 53-63 years and 3258 women aged 48-63 in 2001. MAIN RESULTS: One third of the men and one fifth of the women reported that they had had a ticket fixed at some time. Those who reported having tickets fixed were more likely than the others to report high driving speeds (adjusted odds ratios (aOR) were 1.24, 1.52, and 1.66 in built up areas, on rural roads, and on motorways respectively), to report driving while under the influence (aOR = 1.39), and to report risky use of cellular phone while driving (aOR = 1.83). In addition, participants who reported having tickets fixed were more likely to have had at least one serious road traffic accident in the past 11 years (aOR = 1.21). CONCLUSIONS: Indulgence and the use of connections are common practices in France. These results suggest that it is to confer a feeling of impunity that jeopardises efforts to combat unsafe driving. Abolition of these traditions is essential to ensure the credibility of preventive and repressive measures.

Accident Prevention↗

PubMed2002

Orosomucoid: a mortality risk factor in elderly people living in the community?

AIM: We explored the value of variables relating to inflammation and nutrition as a prognostic factors for mortality in an elderly community-dwelling population. METHODS: We measured plasma levels of orosomucoid, C-reactive protein (CRP), albumin, and transthyretin, and the body mass index (BMI) of 245 subjects aged 65 to 95 living in the community (PAQUID study). The risk of death was analyzed two, four and six years after blood sampling by use of the Cox proportional hazards model with delayed entry. A survival curve was generated by the Kaplan-Meier method. RESULTS: Multivariate analysis--including sex, BMI, and plasma levels of albumin, transthyretin orosomucoid and CRP levels--showed that orosomucoid in the highest quartile (>0.88 g/L) was the strongest predictor of mortality two years after blood sampling [relative risk (RR)=7.4; 95% interval confidence (IC) 2.2-24.6; P<0.1]; the association remained significant four and six years after blood sampling [RR=2.5; 95%IC 1.2-5.2 and RR=1.9; 95%IC 1.0-3.4 respectively, P<0.05]. Orosomucoid levels above 1 g/L (the most accurate threshold for prediction of mortality) were associated with a strong increase in the risk of death two years [RR=12.3; 95%IC 4.3-35.0; P<0.001], four years [RR=6.9; 95%IC 3.3-14.7; P<0.001], and six years [RR=4.4; 95%IC 2.3-8.5; P<0.001) after blood sampling. CONCLUSION: These results further underline the association between systemic inflammation and mortality. They may help us to identify of high-risk subpopulations of elderly subjects so we can employ prevention strategies.

Aged↗

PubMed2001

Prospective measurements of dehydroepiandrosterone sulfate in a cohort of elderly subjects: relationship to gender, subjective health, smoking habits, and 10-year mortality.

The decrease with age of the adrenal-secreted dehydroepiandrosterone sulfate (DHEAS) in serum has suggested that it may be causally related to longevity. For the PAQUID [People (Personnes) Aged (Agées) About What (Quid, in Latin)] cohort of elderly subjects, we have previously reported higher DHEAS in men than in women, a decrease with age and, among men, a negative correlation between the DHEAS level and mortality at 2 and 4 years. Here, with an 8-year followup in 290 subjects, we show a global decrease of 2.3% per year for men and 3.9% per year for women. However, in approximately 30% of cases, there was an increase of DHEAS. We observed no relationship between the evolution of DHEAS level and functional, psychological, and mental status, possibly because of selection by death. In women, no association was found between mortality and DHEAS level. In men, the relative risk (RR) of death was higher for the lowest levels of DHEAS (RR = 1.9, P = 0.007), with RR = 6.5, P = 0.003 for those under 70 years old, a result indicating heterogeneity of the population. There was an effect of subjective health on mortality that disappeared after adjustment of DHEAS levels, suggesting its relation with these DHEAS levels. Death RR was much higher in smokers with a low DHEAS level than in nonsmokers with high DHEAS (RR = 6.7, P = 0.001). We submit that the involvement of DHEAS is possibly different according to gender, that association between low DHEAS level and mortality only for men under 70 years old possibly reflects heterogeneity of the population, and that DHEAS level is a reliable predictor of death in male smokers.

Aged↗

PubMed2001

Structural effects of monovalent anions on polymorphic lysozyme crystals.

Understanding direct salt effects on protein crystal polymorphism is addressed by comparing different crystal forms (triclinic, monoclinic, tetragonal and orthorhombic) for hen, turkey, bob white quail and human lysozymes. Four new structures of hen egg-white lysozyme are reported: crystals grown in the presence of NapTS diffracted to 1.85 A, of NaI to 1.6 A, of NaNO(3) to 1.45 A and of KSCN to 1.63 A. These new structures are compared with previously published structures in order to draw a mapping of the surface of different lysozymes interacting with monovalent anions, such as nitrate, chloride, iodide, bromide and thiocyanate. An analysis of the structural sites of these anions in the various lysozyme structures is presented. This study shows common anion sites whatever the crystal form and the chemical nature of anions, while others seem specific to a given geometry and a particular charge environment induced by the crystal packing.

Amino Acid Sequence↗

PubMed2001

Cholesterol monohydrate nucleation in ultrathin films on water.

The growth of a cholesterol crystalline phase, three molecular layers thick at the air-water interface, was monitored by grazing incidence x-ray diffraction and x-ray reflectivity. Upon compression, a cholesterol film transforms from a monolayer of trigonal symmetry and low crystallinity to a trilayer, composed of a highly crystalline bilayer in a rectangular lattice and a disordered top cholesterol layer. This system undergoes a phase transition into a crystalline trilayer incorporating ordered water between the hydroxyl groups of the top and middle sterol layers in an arrangement akin to the triclinic 3-D crystal structure of cholesterol x H(2)O. By comparison, the cholesterol derivative stigmasterol transforms, upon compression, directly into a crystalline trilayer in the rectangular lattice. These results may contribute to an understanding of the onset of cholesterol crystallization in pathological lipid deposits.

Air↗

PubMed1999

Marital status and risk of Alzheimer's disease: a French population-based cohort study.

OBJECTIVE: To analyze the relationship between marital status and risk of AD or dementia. METHODS: This study was carried out from the Personnes Agées QUID (PAQUID) cohort, an epidemiologic study on normal and pathologic aging after age 65 years. The PAQUID cohort began in 1988. Individuals were followed up at 1, 3, and 5 years, with an active detection of dementia. Marital status was divided into four categories: widowed, never married, divorced or separated, and the reference category, married or cohabitant. The longitudinal relationship between marital status and risk of incident AD or dementia was analyzed by a Cox model with delayed entry. RESULTS: Among the 3,675 individuals initially not demented, 2,106 were married or cohabitants, 1,287 were widowers, 179 were never married, and 103 were divorced or separated. Among the 2,881 individuals reevaluated at least once for the risk of dementia during the 5-year follow-up, 190 incident cases of dementia were identified, including 140 with AD. The relative risks (RRs) of dementia (RR = 1.91, p = 0.018) and of AD (RR = 2.68, p<0.001) were increased for the never-married individuals compared with those who were married or cohabitants. This excess of risk was specifically associated with AD. Adjustment for other risk factors of dementia (education, wine consumption), or for factors reflecting social environment, leisure activities, and depression, did not modify the risk of AD for never-married individuals (RR = 2.31, p = 0.02). CONCLUSIONS: We confirmed an association between marital status and AD, with an excess risk observed among never-married individuals. This association may provide clues about the pathogenesis of AD.

Aged↗

PubMed1999

Early chemoprophylaxis with trimethoprim-sulphamethoxazole for HIV-1-infected adults in Abidjan, Côte d'Ivoire: a randomised trial. Cotrimo-CI Study Group.

BACKGROUND: In sub-Saharan Africa, various bacterial diseases occur before pneumocystosis or toxoplasmosis in the course of HIV-1 infection, and are major causes of morbidity and mortality. We did a randomised, double blind, placebo-controlled clinical trial at community-health centres in Abidjan, Côte d'Ivoire, to assess the efficacy of trimethoprim-sulphamethoxazole (co-trimoxazole) chemoprophylaxis at early stages of HIV-1 infection. METHOD: 843 HIV-infected patients were screened and 545 enrolled in the study. Eligible adults (with HIV-1 or HIV-1 and HIV-2 dual seropositivity at stages 2 or 3 of the WHO staging system) received co-trimoxazole chemoprophylaxis (trimethoprim 160 mg, sulphamethoxazole 800 mg) daily or a matching placebo. The primary outcome was the occurrence of severe clinical events, defined as death or hospital admission irrespective of the cause. Analyses were by intention to treat. FINDINGS: Four of the randomised patients were excluded (positive for HIV-2 only). 120 severe events occurred among 271 patients in the co-trimoxazole group and 198 among 270 in the placebo group. Significantly fewer patients in the co-trimoxazole group than in the placebo group had at least one severe event (84 vs 124); the probability of remaining free of severe events was 63.7% versus 45.8% (hazard ratio 0.57 [95% CI 0.43-0.75], p=0.0001) and the benefit was apparent in all subgroups of initial CD4-cell count. Survival did not differ between the groups (41 vs 46 deaths, p=0.51). Co-trimoxazole was generally well tolerated though moderate neutropenia occurred in 62 patients (vs 26 in the placebo group). INTERPRETATION: Patients who might benefit from co-trimoxazole could be recruited on clinical criteria in community clinics without knowing the patients CD4-cell count. This affordable measure will enable quick public-health intervention, while monitoring bacterial susceptibility and haematological tolerance.

AIDS-Related Opportunistic Infections↗

PubMed1999

The decameric structure of bovine pancreatic trypsin inhibitor (BPTI) crystallized from thiocyanate at 2.7 A resolution.

The structure of a monoclinic form of bovine pancreatic trypsin inhibitor (BPTI) crystallized from a thiocyanate solution has been determined and refined at 2.7 A resolution. The space group is P21 with a = 71.56, b = 73.83, c = 64.47 A, beta = 93.9 degrees and Z = 20. The ten independent molecules were located by a multi-body molecular-replacement search as developed in the AMoRe program, starting from a single monomer model (PDB code: 6PTI). The molecular arrangement of the subunits is a decamer resulting from the combination of two orthogonal fivefold and twofold non-crystallographic axes. This builds a globular micelle-like particle which minimizes hydrophobic interactions with the solvent. The refinement was conducted with non-crystallographic symmetry constraints up to a final residual of R = 0.20 (Rfree= 0.26). The root-mean-square deviations from ideal geometry were 0.015 A and 1.6 degrees on bond distances and bond angles, respectively. Several sites for thiocyanate ions were analyzed.

Animals↗

PubMed1999

[Relation between global cognitive performance and dependency evaluated by the AGGIR scale].

BACKGROUND: The aim of the present study was to investigate the relation between cognitive performances and dependency state according to the AGGIR model, the national standardized instrument determining the attribution of the "Prestation Spécifique Dépendance" (PSD) in France. METHOD: The sample of the study comprised 1,052 subjects aged 73 and over seen at the 8-year follow-up of the Paquid cohort. The "Autonomie Gérontologie Groupes Iso-Ressources" (AG-GIR) model relies on the assessment of eight measures of disability and two additional measures of intellectual coherence and orientation. The model results in a classification of six Iso-Resources Groups (GIR), only the subjects from GIR 1, 2 or 3 being potential beneficiaries of the PSD. RESULTS: The percentage of completely independent subjects (GIR 6) was 85% and only 6.1% were dependent according to the level of the attribution of the PSD (GIR 1 to 3). Among these subjects, 57.8% had been diagnosed as cases of dementia. Conversely, less than half of the cases of dementia were not potential beneficiaries of the PSD. Cognitive performances assessed by the Mini Mental State Examination (MMSE), were associated to a risk of dependency with an odds ratio of 1.4 for the subjects who lost one point on the MMSE (95% CI: 1.3-1.5, p < 0.001). Even when dementia was not diagnosed, low cognitive performances and dyspnea were the main factors of the dependency classification according to the AGGIR model. CONCLUSIONS: This study confirms the relationship between cognitive performances and dependency assessed by the AGGIR model. However the model seems to lack sensitivity for taking into account functional impairment associated with dementia. Consideration of Instrumental Activities of Daily Living in the classification procedure could improve the satisfaction of the needs of these subjects.

Age Factors↗

PubMed1998

Illustration of analysis taking into account complex survey considerations: the association between wine consumption and dementia in the PAQUID study. Personnes Ages Quid.

Epidemiologists are increasingly looking to large-scale sample surveys to provide data for studies of the associations between known or suspected risk factors and disease. More often than not, widely available statistical software packages have been used to analyze such data, particularly when multivariable modeling is involved. Such packages assume that the data have resulted from simple random samples. However, when the survey design incorporates such features as clustering and stratification, the results of statistical analyses based on this assumption can be incorrect. The authors utilized data from the PAQUID (Personnes Agees Quid) study, collected periodically from 1988 to 1996, to illustrate the ease of performing a "design-based" (vs. a "model-based") analysis of complex survey data, and they compared the results obtained using both approaches. The PAQUID study is a stratified cluster sample of elderly community residents in the southwestern departments of Gironde and Dordogne, France. In the illustration presented-in which 3,777 community residents aged 65 years or older were selected to permit identification of baseline and lifetime factors that might be related to cognitive loss, dementia, and Alzheimer's disease--measures of association (such as odds ratios and their associated standard errors) were comparable for both analytical strategies. However, this may not be the case for other examples. Descriptive measures (such as estimates of means and proportions) may be more seriously compromised by the decision to ignore the sampling design. The availability of modern statistical packages with survey analysis capabilities should encourage data analysts to perform design-based analyses whenever possible.

Aged↗

PubMed1998

Analysis of error types in the trial making test evidences an inhibitory deficit in dementia of the Alzheimer type.

Several studies have reported low performances of patients with dementia of the Alzheimer Type (DAT) on the Trial Making Test (TMT), however, these studies were not designed to identify specific operations underlying this impairment. To better understand the attentional disorder in DAT, we analyzed the performances of patients with DAT and matched elderly adults on the TMT, with a detailed analysis of error types. The analysis showed that 67% of patients' errors were related to an inhibitory deficit versus only 24% in normal elderly adults. Therefore, it was suggested that inefficient inhibitory mechanisms are responsible, to a large extent, for the poor TMT performance of patients with DAT, supporting the hypothesis of an inhibitory dysfunction in DAT.

Adult↗

PubMed1997

Different tools to study interaction potentials in gamma-crystallin solutions: relevance to crystal growth.

Osmotic pressure, small-angle X-ray scattering and quasi-elastic light scattering were used to study the medium-range interaction potentials between macromolecules in solution. These potentials determine macromolecular crystallization. Calf eye lens gamma-crystallins were used as a model system with the charge, and therefore the interactions, varied with pH. The second virial coefficient was determined under the same conditions with each of the three techniques. Osmotic pressure and quasi-elastic light scattering can be used conveniently in the laboratory to rapidly test the type of interactions (either attractive or repulsive) present in the solution. The measurement is direct with osmotic pressure, whereas with quasi-elastic light scattering, the directly measured coefficient is a combination of thermodynamic and hydrodynamic terms. X-rays, which require more sophisticated equipment such as synchrotron radiation facilities, can provide more detailed information on the interparticle potentials when models are used. At low ionic strength, two potentials were found necessary to account for the temperature and pH phase diagram as a function of protein concentration. The first potential is the van der Waals attractive potential that was previously shown to account for the fluid-fluid phase separation at low temperature. The second potential is an electrostatic coulombic repulsive potential which is a function of the protein charge and thus of the pH. The interaction trail could be followed at protein concentrations as low as 10 mg ml(-1). The results as a whole are expected to be valid for all compact low molecular weight proteins at low ionic strength.

Journal Article↗

PubMed1997

[Is it possible to improve sleep in children? A research on health education in nursery schools].

An educational project in nursery schools was carried out with the aim to improve children's sleep. Its effectiveness was tested in terms of awareness of families and length of sleep of children. The method was a prevention trial based on the random division of classes of 3-year old into two groups (intervention group and control group) comprising children enrolled in nursery schools in the Rhône region (France) in 1992. The project, lasting 2 years, relied on physicians from the community (Maternal, Child Health Service and School Health Service), their role being to mobilise the teaching teams, distribute specific teaching tools and raise awareness of families to respect the sleep patterns of children, during routine medical examinations. The study was carried out in 140 nursery schools with 1,500 children in each group. The evaluation was based on the application of a logistical regression model taking potentially confounding factors into account, and an analysis in sub-groups in order to demonstrate the effectiveness of intervention on particularly exposed groups. The results show: 1) the feasibility of such an intervention among nursery school children on a large scale, 2) the effectiveness of the action, with a reduction of the risk of "poor knowledge" among parents (OR = 0.76), particularly in urban areas, and a reduction in the risk "short nights" in the sub-group of children who had " little sleep at 3 years" in low social class families (OR = 0.50).

Child, Preschool↗