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Biomedical subjects

P H Langlois

Publications and source records attributed to P H Langlois.

7 recordsLinked to original sources
PubMed2005

Relation between ambient air quality and selected birth defects, seven county study, Texas, 1997-2000.

A population-based case-control study investigated the association between maternal exposure to air pollutants, carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter <10 microm in aerodynamic diameter during weeks 3-8 of pregnancy and the risk of selected cardiac birth defects and oral clefts in livebirths and fetal deaths between 1997 and 2000 in seven Texas counties. Controls were frequency matched to cases on year of birth, vital status, and maternal county of residence at delivery. Stationary monitoring data were used to estimate air pollution exposure. Logistic regression models adjusted for covariates available in the vital record. When the highest quartile of exposure was compared with the lowest, the authors observed positive associations between carbon monoxide and tetralogy of Fallot (odds ratio = 2.04, 95% confidence interval: 1.26, 3.29), particulate matter <10 microm in aerodynamic diameter and isolated atrial septal defects (odds ratio = 2.27, 95% confidence interval: 1.43, 3.60), and sulfur dioxide and isolated ventricular septal defects (odds ratio = 2.16, 95% confidence interval: 1.51, 3.09). There were inverse associations between carbon monoxide and isolated atrial septal defects and between ozone and isolated ventricular septal defects. Evidence that air pollution exposure influences the risk of oral clefts was limited. Suggestive results support a previously reported finding of an association between ozone exposure and pulmonary artery and valve defects.

Air Pollutants↗
PubMed2001

The National Birth Defects Prevention Study.

The National Birth Defects Prevention Study was designed to identify infants with major birth defects and evaluate genetic and environmental factors associated with the occurrence of birth defects. The ongoing case-control study covers an annual birth population of 482,000 and includes cases identified from birth defect surveillance registries in eight states. Infants used as controls are randomly selected from birth certificates or birth hospital records. Mothers of case and control infants are interviewed and parents are asked to collect buccal cells from themselves and their infants for DNA testing. Information gathered from the interviews and the DNA specimens will be used to study independent genetic and environmental factors and gene-environment interactions for a broad range of birth defects. As of December 2000, 7,470 cases and 3,821 controls had been ascertained in the eight states. Interviews had been completed with 70% of the eligible case and control mothers, buccal cell collection had begun in all of the study sites, and researchers were developing analysis plans for the compiled data. This study is the largest and broadest collaborative effort ever conducted among the nation's leading birth defect researchers. The unprecedented statistical power that will result from this study will enable scientists to study the epidemiology of some rare birth defects for the first time. The compiled interview data and banked DNA of approximately 35 categories of birth defects will facilitate future research as new hypotheses and improved technologies emerge.

Case-Control Studies↗
PubMed1995

Diurnal variation in responses to influenza vaccine.

Data from two field trials of influenza vaccine were examined for an association between vaccination time and subject response. Both were conducted on adults and involved the same antigens and dose via intramuscular injection. In one study (Princeton) a diurnal pattern in antibody response to the antigen A/Philippines, but not to A/Chile or B/USSR, was detected after the first vaccination administered during summer 1984, but not after the second revaccination given during summer 1985. In a second study (Houston) conducted during autumn 1985, no diurnal pattern in antibody response was detected for any of the antigens assessed. No diurnal pattern in systemic reactions was observed. Previously vaccinated subjects of both studies more commonly experienced local reactions of arm redness, hardness, and soreness after afternoon versus morning (p < 0.05) injection upon revaccination, both before and after adjustment for possible confounders of age and gender.

Adult↗
PubMed1985

Temporal patterns of reported single-vehicle car and truck accidents in Texas, U.S.A. during 1980-1983.

Reported single car and truck accidents due specifically to driver 'fatigue' for the 4-year span of 1980-1983 were analyzed for 24-hr, 7-d and 1-yr patterns. Three types of data were examined: (1) accidents in rural Texas, (2) accidents only in San Antonio, the fourth largest city in Texas and (3) accident ratio (number of accidents per time interval divided by traffic volume for the interval) in this city. A statistically significant seasonal variation of relatively low amplitude with peaks in May and July was detected only for accidents in rural areas. High-amplitude periodicities of 7 d were evident in all the data sets, with a peak on the weekend. A very prominent 24-hr pattern was detected as well, with the acrophase determined by single cosinor around 0300. A slight secondary peak in accidents, around 1500, was evident in the data from the rural areas. This secondary peak represented a 12-hr rhythm in addition to the 24-hr. Overall, features of the temporal patterns in accidents over 24 hr and over the year in urban and rural areas differed only slightly. Accident ratios yielded results similar to accident frequencies. However, with regard to the rural data, the shape of the 24-hr temporal pattern varied with driver age; older drivers exhibited a flatter curve with a more pronounced afternoon rather than early morning (around 0300) peak.

Accidents, Traffic↗
PubMedDate not supplied

A comparison of the health status of Riverdale residents with residents of the rest of Toronto based on the Toronto Community Health Survey.

OBJECTIVES: To compare the health status of Riverdale residents with residents of the rest of Toronto. DESIGN: Cross-sectional telephone survey. SETTING: Toronto. TIME FRAME: October 1988-June 1989. PARTICIPANTS: Four hundred and fourteen residents of Riverdale, a residential-industrial area of Toronto, and 866 residents of the rest of Toronto, age 15 years and older in households with telephones. MAIN RESULTS: Respondents in Riverdale compared to respondents in the rest of Toronto were more likely to speak languages other than English, have less formal education, and be of Oriental ethnic origin. Perceived health status varied between the two areas, but no significant difference existed in diagnosed morbidity. Riverdale respondents were much more aware of food and soil contamination than respondents from the rest of Toronto.

Adolescent↗
PubMedDate not supplied

Toronto tap water: perception of its quality and use of alternatives.

A cross-sectional telephone survey determined attitudes of City of Toronto residents toward the quality of their tap water, and their usage of alternative drinking water sources. Overall, 49% of households rated the water as good or very good, although 73% felt that it contained some or a lot of chemical pollutants. An alternative to tap water was used by 40.5% of households; 35% were 'regular' users, obtaining at least 50% of their consumed water this way. In terms of specific alternatives, 22.5% of households consumed bottled water, 11% treated tap water additionally with a home device, and 12% boiled their water. For 'regular users', the proportions were 19.5%, 10% and 10% respectively. This surprisingly high and probably increasing usage of alternatives may have implications for regulation.

Attitude to Health↗