Association between prenatal care and small for gestational age birth: an ecological study in Quebec, Canada. / Lien entre les soins prénataux et le faible poids pour l'âge gestationnel à la naissance : une étude écologique au Québec (Canada).

BACKGROUND: In Quebec, women living on low income receive a number of additional prenatal care visits, determined by their area of residence, of both multi-component and food supplementation programs. We investigated whether increasing the number of visits reduces the odds of the main outcome of small for gestational age (SGA) birth (weight < 10th percentile on the Canadian scale). METHODS: In this ecological study, births were identified from Quebec's registry of demographic events between 2006 and 2008 (n = 156 404; 134 areas). Individual characteristics were extracted from the registry, and portraits of the general population were deduced from data on multi-component and food supplement interventions, the Canadian census and the Canadian Community Health Survey. Mothers without a high school diploma were eligible for the programs. Multilevel logistic regression models were fitted using generalized estimating equations to account for the correlation between individuals on the same territory. Potential confounders included sedentary behaviour and cigarette smoking. The odds ratios (ORs) were adjusted for mother's age, marital status, parity, program coverage and mean income in the area. RESULTS: Mothers eligible for the programs remain at a higher odds of SGA than non-eligible mothers (OR = 1.40; 95% confidence interval [CI]: 1.30-1.51). Further, areas that provide more visits to eligible mothers (4-6 food supplementation visits) seem more successful at reducing the frequency of SGA birth than those that provide 1-2 or 3 visits (OR = 0.86; 95% CI: 0.75-0.99). CONCLUSION: Further studies that validate whether an increase in the number of prenatal care interventions reduces the odds of SGA birth in different populations and evaluate other potential benefits for the children should be done.

INTRODUCTION: Au Québec, les femmes vivant avec un faible revenu reçoivent un certain nombre de visites de soins prénataux supplémentaires, en fonction de leur lieu de résidence, dans le cadre d'un programme à multiples composantes et d'un programme d'intervention comprenant des suppléments alimentaires. Nous avons examiné si l'augmentation du nombre de visites réduisait le risque de faible poids pour l'âge gestationnel à la naissance (poids inférieur au 10e percentile sur l'échelle canadienne). MÉTHODOLOGIE: Pour cette étude écologique, nous avons sélectionné les naissances dans le registre des événements démographiques du Québec entre 2006 et 2008 (n = 156 404; 134 secteurs). Les caractéristiques individuelles ont été extraites du registre des naissances alors que les portraits de la population générale ont été déduits de données sur l'intervention à multiples composantes et du programme d'intervention comprenant des suppléments alimentaires, ainsi que des recensements canadiens et des Enquêtes sur la santé dans les collectivités canadiennes. Ont été considérées comme admissibles aux programmes les mères sans diplôme d'études secondaires. Les modèles de régression logistique multiniveaux ont été ajustés à l'aide d'équations d'estimation généralisées pour tenir compte de la corrélation entre les individus vivant sur un même territoire. Les principaux facteurs confusionnels potentiels étaient la sédentarité et le tabagisme. Les rapports de cotes (RC) ont été ajustés en fonction de l'âge, de l'état matrimonial et de la parité de la mère ainsi que de la couverture du programme et du revenu moyen dans le secteur. RÉSULTATS: Les mères admissibles aux programmes se sont révélées plus à risque de donner naissance à un bébé de faible poids pour l'âge gestationnel à la naissance que les autres mères (RC = 1,40; intervalle de confiance [IC] à 95 % : 1,30 à 1,51). De plus, les secteurs offrant un plus grand nombre de visites aux mères admissibles (4 à 6 visites dans le cadre du programme d'intervention comprenant des suppléments alimentaires) semblent mieux réussir à réduire la fréquence du faible poids pour l'âge gestationnel à la naissance que ceux offrant soit 1 ou 2 visites, soit 3 visites (RC = 0,86; IC à 95 % : 0,75 à 0,99). CONCLUSION: Il est nécessaire de conduire des études supplémentaires pour valider qu'une augmentation du nombre d'interventions en soins prénataux réduit le risque de faible poids pour l'âge gestationnel à la naissance au sein de différentes populations et pour en évaluer d'autres avantages potentiels pour les enfants.

The IVAIRE project--a randomized controlled study of the impact of ventilation on indoor air quality and the respiratory symptoms of asthmatic children in single family homes.

UNLABELLED: A randomized controlled trial was carried out to measure the impact of an intervention on ventilation, indoor air contaminants, and asthma symptoms of children. Eighty-three asthmatic children living in low-ventilated homes were followed over 2 years. Several environmental parameters were measured during the summer, fall, and winter. The children were randomized after Year 1 (43 Intervention; 40 Control). The intervention included the installation of either a Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV). During the fall and winter seasons, there was a significant increase in the mean ventilation rate in the homes of the intervention group. A statistically significant reduction in mean formaldehyde, airborne mold spores, toluene, styrene, limonene, and α-pinene concentrations was observed in the intervention group. There was no significant group difference in change in the number of days with symptoms per 14 days. However, there was a significant decrease in the proportion of children who experienced any wheezing (≥1 episode) and those with ≥4 episodes in the 12-month period in the intervention group. This study indicates that improved ventilation reduces air contaminants and may prevent wheezing. Due to lack of power, a bigger study is needed. PRACTICAL IMPLICATIONS: Positive findings from this study include the fact that, upon recruitment, most of the single family homes with asthmatic children were already equipped with a mechanical ventilation system and had relatively good indoor air quality. However, the 8-h indoor guideline for formaldehyde (50 µg/m3) was frequently exceeded and the ventilation rates were low in most of the homes, even those with a ventilation system. Both ERVs and HRVs were equally effective at increasing air exchange rates above 0.30 ACH and at preventing formaldehyde concentrations from exceeding the 50 µg/m3 guideline during the fall and winter seasons. Furthermore, the ERVs were effective at preventing excessively low relative humidities in the homes. Based on observed difference of risk, intervention to increase ventilation in five sample homes and children would prevent 1 home to exceed the indoor air long-term formaldehyde guideline and prevent 1 asthmatic child experiencing at least one episode of wheezing over a year.

Impact of individual and ecological characteristics on small for gestational age births: an observational study in Quebec.

INTRODUCTION: We evaluated associations between ecological variables and the risk of very small for gestational age (VSGA) birth in Quebec in 2000-2008. METHODS: Ecological variables came from the Canadian Community Health Survey, the Canadian census and Quebec's birth registry; individual variables also came from Quebec's birth registry. Odds ratios (ORs) adjusted for mother's age, academic qualification, parity, marital status and country of birth were estimated using multilevel logistic regression (generalized estimating equations method). RESULTS: Births in neighbourhoods with a high proportion of people leading a sedentary lifestyle (OR: 1.07, 95% confidence interval [CI]: 1.01-1.11) and those with a high/middle proportion of residents with food insecurity (OR: 1.09, 95% CI: 1.05-1.15; OR: 1.05, 95% CI: 1.01-1.11) had higher odds of VSGA birth. Those with middle proportion of married residents had lower odds of VSGA birth (OR: 0.94, 95% CI: 0.90-0.98).

TITRE: Incidence des caractéristiques individuelles et des caractéristiques du contexte sur les nouveau-nés de faible poids : une étude d'observation au Québec. INTRODUCTION: Nous avons analysé les liens entre certaines variables contextuelles, certaines caractéristiques des mères et le risque de donner naissance à des nouveau-nés très petits pour l'âge gestationnel (TPAG) au Québec entre 2000 et 2008. MÉTHODOLOGIE: Les variables liées au contexte ont été tirées de l'Enquête sur la santé dans les collectivités canadiennes, du Recensement canadien et du Registre des naissances du Québec. Les variables individuelles provenaient aussi du Registre des naissances du Québec. Les rapports de cotes (RC), ajustés selon l'âge de la mère, la scolarité, la parité, l'état matrimonial et le pays de naissance, ont été évalués au moyen de modèles de régression logistique multiniveau (par des équations d'estimation généralisées). RÉSULTATS: Les naissances survenues dans les quartiers présentant une proportion élevée de résidents sédentaires (RC : 1,07, intervalle de confiance [IC] à 95% : 1,01 à 1,11) et dans les quartiers présentant une proportion moyenne (RC : 1,09, IC à 95% : 1,05 à 1,15) ou élevée de résidents souffrant d'insécurité alimentaire (RC : 1,05, IC à 95% : 1,01 à 1,11) présentaient un risque accru d'être TPAG. Le risque de naissance de nouveau-né TPAG était plus faible dans les quartiers présentant une proportion moyenne de résidents mariés (RC : 0,94, IC à 95 % : 0,90 à 0,98).

Risk of infectious gastroenteritis in young children living in Québec rural areas with intensive animal farming: results of a case-control study (2004-2007).

This study was designed to evaluate the epidemiology of severe gastroenteritis in children living in Québec rural areas with intensive livestock activities. From September 2005 through June 2007, 165 cases of gastroenteritis in children aged from 6 months to 5 years, hospitalized or notified to the public health department were enrolled, and 326 eligible controls participated. The parents of cases and controls were asked questions about different gastroenteritis risk factors. The quality of the drinking water used by the participants was investigated for microbial indicators as well as for four zoonotic bacterial pathogens (Campylobacter spp, Escherichia coli, Salmonella spp and Yersinia spp) and two enteric parasites (Cryptosporidium spp and Giardia spp). From 134 stool specimen analysed, viruses were detected in 82 cases (61%), while 28 (21%) were found with at least one of the bacteria investigated, and five cases were infected by parasites. Campylobacteriosis was the main bacterial infection (n = 15), followed by Salmonella sp (n = 7) and E. coli O157:H7 (n = 5) among cases with bacterial gastroenteritis. No significant difference was found between cases and controls regarding the quality of water consumed; the frequency of faecal contamination of private wells was also similar between cases and controls. Considering the total cases (including those with a virus), no link was found between severe gastroenteritis and either being in contact with animals or living in a municipality with the highest animal density (4th quartile). However, when considering only cases with a bacterial or parasite infection (n = 32), there was a weak association with pig density that was not statistically significant after adjusting for potential confounders. Contact with domestic, zoo or farm animals were the only environmental factor associated with the disease.

Association between potential zoonotic enteric infections in children and environmental risk factors in Quebec, 1999-2006.

This study was designed to evaluate the association of potential zoonotic gastroenteritis in children, and specifically giardiasis, salmonellosis and campylobacteriosis, with environmental risk factors in rural areas of Quebec. Notified cases of gastroenteritis in children of 0-4 years of age reported in the period of 1999 through 2006 from municipalities in southern Quebec with <100,000 inhabitants were investigated. Negative binomial regression models accounting for overdispersion and adjusted for clustering were used to estimate relative risks (RR) associated with livestock densities and drinking water quality. Analyses revealed that, during this period, 2500 cases of gastroenteritis were reported in children of 0-4 years, including 819 cases of giardiasis, 690 of salmonellosis and 852 of campylobacteriosis. The incidence rate associated with all potential zoonotic agents reported was 163 cases/100,000 children-years and this was statistically associated with cattle density: RR Quartile 4/Quartile 1 (Q4/Q1) = 1.92, 95% CI = 1.43-2.58. When estimated specifically for each pathogen, incidence rates of giardiasis (RR Q4/Q1 = 1.79, 95% CI = 1.11-2.87), salmonellosis (RR Q4/Q1 = 1.64, 95% CI = 1.15-2.33) and campylobacteriosis (RR Q4/Q1 = 2.43, 95% CI = 1.60-3.68) were also associated with cattle density, with a monotonic increase of RR with increasing animal density. Giardiasis incidence was also positively associated with a poor drinking water quality, although no statistically significant association was found. Our results suggest that, in rural Quebec, bacterial and parasitic enteric infections in young children may be zoonoses related to environmental risk factors and especially cattle production.

Association between indicators of livestock farming intensity and hospitalization rate for acute gastroenteritis.

To evaluate associations between indicators of livestock farming intensity (manure surplus and livestock density) and acute gastroenteritis hospitalization (AGH) rate, we conducted an ecological study on 306 selected agricultural municipalities of Quebec. We estimated the AGH rate for the period 2000-2004 from the Quebec hospital database. Multivariate Poisson regression was used to estimate the strength of association between the farming indicators and AGH with adjustment for confounders. The modifying effect of age and water source was also evaluated. Association between manure and AGH was observed in children, especially those aged 0-4 years for selected zoonotic infections [adjusted hospitalization rate ratio (aHRR) 1.93, 95% CI 1.21-3.09]. The risk ratio was higher for subjects using ground-water source. An increasing HRR trend with each additional level of poultry density was observed in children aged 0-4 years, especially for Salmonella infections. We conclude that livestock farming intensity may be linked to bacterial acute gastroenteritis in children.

Assessment of microbiological quality of drinking water from household tanks in Bermuda.

Bermuda residents collect rainwater from rooftops to fulfil their freshwater needs. The objective of this study was to assess the microbiological quality of drinking water in household tanks throughout Bermuda. The tanks surveyed were selected randomly from the electoral register. Governmental officers visited the selected household (n = 102) to collect water samples and administer a short questionnaire about the tank characteristics, the residents' habits in terms of water use, and general information on the water collecting system and its maintenance. At the same time, water samples were collected for analysis and total coliforms and Escherichia coli were determined by 2 methods (membrane filtration and culture on chromogenic media, Colilert kit). Results from the 2 methods were highly correlated and showed that approximately 90% of the samples analysed were contaminated with total coliforms in concentrations exceeding 10 CFU/100 mL, and approximately 66% of samples showed contamination with E. coli. Tank cleaning in the year prior to sampling seems to protect against water contamination. If rainwater collection from roofs is the most efficient mean for providing freshwater to Bermudians, it must not be considered a source of high quality drinking water because of the high levels of microbial contamination.

Suppressor of cytokine signaling-1 is an IL-4-inducible gene in macrophages and feedback inhibits IL-4 signaling.

Interferon-gamma and interleukin-4 (IL-4) induce distinct gene expression profiles in macrophages by differentially activating signal transducers and activators of transcription (STAT)1 and STAT6, respectively. The role of suppressor of cytokine signaling (SOCS)-1 as a negative regulator of IFN-gamma signaling is well established. However, its potential role as a negative regulator of IL-4 signaling has not been explored. We found that IL-4, like IFN-gamma, induces rapid de novo expression of SOCS-1 in primary macrophages. Induction of SOCS-1 gene expression by IL-4 is STAT6-dependent, whereas induction of SOCS-1 by IFN-gamma is STAT1-dependent. Unlike their common ability to induce expression of SOCS-1, IL-4 also induced expression of SOCS-2 but not SOCS-3 in macrophages, whereas IFN-gamma induced expression of SOCS-3 but not SOCS-2. Forced expression of SOCS-1 or SOCS-3, but not SOCS-2, inhibited activation of STAT6 by IL-4. Moreover, SOCS-1 appears to serve as an endogenous regulator of IL-4 signaling in macrophages because the magnitude and duration of STAT6 activation as well as IL-4-mediated gene expression were much greater in SOCS-1-deficient (SOCS-1(-/-)) macrophages than in wild-type macrophages. Our findings demonstrate that, like IFN-gamma, IL-4 also induces expression of SOCS-1 in macrophages, and SOCS-1 feedback inhibits expression of STAT6-responsive genes.

[Environmental hazards for falls in elders in low income housing]. / Dangers environnementaux de chute dans des habitations à loyer modique pour personnes âgées.

BACKGROUND: About 35% of elders living at home fall each year. The objectives of this study were to evaluate the environmental hazards associated with falls in 58 low income housings for elders and to determine the contribution of environmental factors to these falls. METHODS: Participants were interviewed to document their health problems, their knowledge concerning the Issue of falls, and their history of falls during the last year. Environmental hazards were identified and evaluated with a standardised checklist. The levels of hazards (percentage of factors identified which represent a hazard) were measured for the different sectors and for the entire dwelling and communal spaces. The hazards were also evaluated according to four main variables (structure of the building, characteristics of the floor surface, environmental obstacles, risk-taking behaviour). RESULTS: A total of 172 participants were recruited for the study. For dwellings and communal spaces, the hazards were respectively higher in bathrooms (mean=27.0%; p<0.05) and interior stairs (mean=22.5%; p<0.05). For the communal spaces of buildings of less than 20 Years, the global hazard was higher in the smaller buildings (three stories, mean=12.6%; p<0.001). For dwellings of the larger buildings, the global hazard was higher for younger buildings (<20 years, mean=16.6%; >or=20 years, mean=13.5%; p<0.001). Among the variables documented, risk-taking behaviour was the more frequent factor for the dwellings (mean=32.0%; p<0.05) as for the communal spaces (mean=42.5%; p<0.05). Finally, only 34% of the participants mentioned receiving information concerning the falls among elders. Among the 27 falls documented, an environmental factor was identified in 55% of the cases. CONCLUSION: The study helped to document the presence of environmental factors which could be a hazard for falls in elders' housing and to suggest preventive and remedial actions.

Effects of electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin.

In 1998, the authors studied the effect of residential exposure to electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin (6-OHMS) in the Quebec city, Canada, metropolitan area. A sample of 221 women living near a 735-kV line was compared with 195 women the same age living away from any power lines. Participants provided morning urine samples on 2 consecutive days and wore a magnetic dosimeter for 36 consecutive hours to measure personal magnetic exposure. The indoor electric field was assessed by spot measurements. After adjustment for other factors associated with low melatonin secretion, such as medication use or light exposure, nighttime concentration of 6-OHMS was similar in the two groups. When either 24-hour or sleep-time exposure to magnetic field or electric field measurements was used, no exposure-effect relation was evident. However, the trend of decreasing 6-OHMS concentration with age was more pronounced for women living near the lines, as was a lower 6-OHMS concentration in women with high body mass index. Chronic residential exposure to magnetic fields from high-power lines may accentuate the decrease in melatonin secretion observed in some vulnerable subgroups of the population.

Relations between n-3 fatty acid status and cardiovascular disease risk factors among Quebecers.

BACKGROUND: Epidemiologic evidence shows an inverse relation between fish consumption and death from ischemic heart disease. This beneficial effect is attributed to n-3 fatty acids. OBJECTIVES: The purpose of this study was to examine the association between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among Quebecers. DESIGN: The study population consisted of 1460 subjects aged 18-74 y who participated in the 1990 Quebec Heart Health and Nutrition Survey. Data were obtained through home interviews and clinic visits. RESULTS: Expressed as the percentage of total fatty acids in plasma phospholipids, the geometric means of EPA, DHA, and their combination were 0.47%, 1.19%, and 1.70%, respectively. Concentrations of n-3 fatty acids were positively associated with fish intake. We found positive associations between EPA and total cholesterol, LDL cholesterol, HDL cholesterol, plasma glucose, and systolic and diastolic blood pressure. We found positive associations between DHA and total cholesterol, the ratio of total to HDL cholesterol, triacylglycerols, systolic blood pressure, and plasma glucose and insulin. We also found positive associations between the ratio of EPA to arachidonic acid and total cholesterol, HDL cholesterol, and systolic blood pressure and a negative association with the ratio of total to HDL cholesterol. CONCLUSIONS: Our results indicate that concentrations of EPA and DHA in plasma phospholipids reflected Quebecer fish consumption. Results also show that EPA and the ratio of EPA to arachidonic acid can positively influence HDL-cholesterol concentrations.

n-3 Fatty acids and cardiovascular disease risk factors among the Inuit of Nunavik.

BACKGROUND: Inuit traditionally consume large amounts of marine foods rich in n-3 fatty acids. Evidence exists that n-3 fatty acids have beneficial effects on key risk factors for cardiovascular disease. OBJECTIVE: Our goal was to verify the relation between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among the Inuit of Nunavik, Canada. DESIGN: The study population consisted of 426 Inuit aged 18-74 y who participated in a 1992 health survey. Data were obtained through home interviews and clinical visits. Plasma samples were analyzed for phospholipid fatty acid composition. RESULTS: Expressed as the percentage of total fatty acids, geometric mean concentrations of EPA, DHA, and their combination in plasma phospholipids were 1.99%, 4.52%, and 6.83%, respectively. n-3 Fatty acids were positively associated with HDL-cholesterol concentrations and inversely associated with triacylglycerol concentrations and the ratio of total to HDL cholesterol. In contrast, concentrations of total cholesterol, LDL cholesterol, and plasma glucose increased as n-3 fatty acid concentrations increased. There were no significant associations between n-3 fatty acids and diastolic and systolic blood pressure and plasma insulin. CONCLUSIONS: Consumption of marine products, the main source of EPA and DHA, appears to beneficially affect some cardiovascular disease risk factors. The traditional Inuit diet, which is rich in n-3 fatty acids, is probably responsible for the low mortality rate from ischemic heart disease in this population.

Multiple signal transduction pathways mediate interleukin-4-induced 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase in normal and tumoral target tissues.

The 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase (3beta-HSD) isoenzymes catalyze an essential step in the formation of all classes of active steroid hormones. We have recently shown that 3beta-HSD type 1 gene expression is specifically induced by interleukin (IL)-4 and IL-13 in several human cancer cell lines and in normal human mammary and prostatic epithelial cells in primary culture. There is evidence that IL-4 stimulates bifurcating signaling pathways in which the Stat6-signal pathway is involved in differentiation and gene regulation, whereas insulin receptor substrate (IRS) proteins mediate the mitogenic action of IL-4. As a matter of fact, we have shown that IL-4-activated Stat6 in all cell lines studied, where IL-4 induced 3beta-HSD type 1 expression but not in those cell lines that failed to respond to IL-4. The mechanism of the induction of 3beta-HSD type 1 gene expression was further characterized in ZR-75-1 human breast cancer cells. We have also found that IL-4 rapidly induced IRS-1 and IRS-2 phosphorylation in these cell lines. Moreover, insulin-like growth factor (IGF)-1 and insulin, which are well known to cause IRS-1 and IRS-2 phosphorylation, increased the stimulatory effect of IL-4 on 3beta-HSD activity. IRS-1 and IRS-2 are adapter molecules that provide docking sites for different SH2 domain-containing proteins, leading to the activation of multiple pathways, such as the phosphatidylinositol (PI) 3-kinase and the mitogen-activated protein (MAP) pathways. The inhibition of IL-4-induced 3beta-HSD expression by PI 3-kinase inhibitors (wortmannin and LY294002) as well as an inhibitor of MAP kinase activation (PD98059), indicates the involvement of those pathways in this response to IL-4. Wortmannin also blocked MAP kinase activation by IL-4, insulin and IGF-1 suggesting that the MAP kinase cascade acts as a downstream effector of PI 3-kinases. Furthermore, we showed that the PKC activator phorbol-12-myristate-13-acetate (PMA) also potentiated the IL-4-induced 3beta-HSD activity, thus suggesting that one signaling molecule that is involved in the signal transduction of the IL-4 action on 3beta-HSD type 1 expression is also a substrate for PKC. Taken together, these findings suggest the existence of a novel mechanism of gene regulation by IL-4. This mechanism would involve in the phosphorylation of IRS-1 and IRS-2, which transduce the IL-4 signal through a PI 3-kinase- and MAP kinase-dependent signaling pathway. However, the inability of IGF-1, insulin and PMA to stimulate 3beta-HSD type 1 expression by themselves in the absence of IL-4 indicates that the multiple pathways downstream of IRS-1 and IRS-2 must act in cooperation with an IL-4-specific signaling molecule, such as the transcription factor Stat6. It is also of interest to note that there also appear to be differences between the regulation of the 3beta-HSD type 1 and type 2 promoters.

Evaluation of a modified sanitary napkin as a sample self-collection device for the detection of genital chlamydial infection in women.

A modified sanitary napkin was compared with endocervical swab and urine specimens for the detection of urogenital Chlamydia trachomatis infection. Endocervical swabs and/or first-catch urine were collected from 510 women at medical or community settings in Quebec City. Participants were also asked to wear a modified sanitary napkin (Ezy-Detek) during 4 consecutive hours and to bring it back to the clinic or mail it to the laboratory. Endocervical and urine specimens were tested using the Cobas Amplicor CT/NG assay (Roche Diagnostic Systems) according to the manufacturer's instructions, as were specimens collected with the napkin after adequate preparation. If the PCR test result was positive on the endocervical sample or on any two samples, a woman was considered to be infected. PCR testing results on paired samples were identical for 493 (96.6%) of 510 women. According to the definition given above, 58 (11.3%; 95% confidence interval [CI], 8.7 to 14.5%) women were infected with C. trachomatis. The sensitivity and specificity of PCR testing on modified sanitary napkin specimens were, respectively, 93.1% (54 of 58; 95% CI, 83.3 to 98.1%) and 98.9% (447 of 452; 95% CI, 97.4 to 99.6%) compared to 81.0% (47 of 58; 95% CI, 68.6 to 90.1%) and 100% (451 of 451; 95% CI, 99.2 to 100%) for urine specimens. The positive and negative predictive values were, respectively, 91.5% (54 of 59) and 99.1% (447 of 451) for the sanitary napkin specimens compared to 100% (47 of 47) and 97.6% (451 of 462) for urine samples. These results suggest that a modified sanitary napkin represents an effective noninvasive device for self-collection of specimens to detect urogenital C. trachomatis infection.

Crucial role of cytokines in sex steroid formation in normal and tumoral tissues.

There is evidence suggesting that local intracrine formation of sex steroids from inactive precursors, dehydroepiandrosterone (DHEA), its sulfate (DHEA-S) and 4-androstenedione (4-DIONE) plays an important role in the regulation of growth and function of peripheral target tissues. Moreover, human solid tumors are often infiltrated by stromal/immune cells secreting a wide spectra of cytokines. These cytokines might in turn regulate the activity of both immune and neoplastic cells. Our data demonstrate that the potent regulatory effects of interleukin-4 (IL-4) and IL-6 on both estrogenic and androgenic 17beta-HSD/KSR activities in breast cancer cells depend on the cell-specific gene expression of various types of 17beta-HSD/KSR enzymes. However, in both estrogen-receptor (ER)-positive (ZR-75-1, T-47D) and ER-negative (MDA-MB-231, BT-20) human breast cancer cells, exposure to IL-4 and IL-13 caused a rapid and potent induction of 3beta-HSD type 1 gene expression. Such an induction was also observed in normal human mammary and prostate epithelial cells in primary culture as well as in human HaCaT immortalized keratinocytes, ME-180 cervix cancer cells, and HT-29 colon cancer cells. The DNA-binding activity of Stat6, a member of the Signal Transducers and Activators of Transcription gene family, was activated after a 30 min exposure to IL-4 in all the cell types where IL-4 induced 3beta-HSD expression, but not in those that failed to respond to IL-4. Our data therefore suggest that IL-4 and IL-13 may play a role in the biosynthesis of active sex steroids from the inactive adrenal steroid DHEA, not only in breast cells but also in various cell types derived from peripheral target tissues.

Wood-burning appliances and indoor air quality.

Wood heating represents an interesting economic alternative to electrical or heating oil and gas systems. However, many people are concerned about poor indoor air quality in homes equipped with wood-burning appliances. We conducted a study in the Quebec City region (Canada) to verify the extent of indoor air contamination, and to examine the frequency of respiratory symptoms and illnesses among occupants of wood-heated homes. One child attending primary school (median = 8 years old; range = 5-14 years old) and an adult (median = 37 years old; range = 23-52 years old) were recruited in each eligible house. Eligible houses were without known sources of combustion products (smokers, attached garage, oil or gas furnace, gas stove, etc.) except for wood-burning appliance. Out of the 89 houses included in the study, 59 had wood-burning appliances. Formaldehyde, nitrogen dioxide, respirable particles (PM10) and carbon monoxide were measured in a sub-set of 49 houses (41 with a wood-burning appliance and 8 without). The frequency of respiratory symptoms and diseases among participants were documented using a daily symptom diary. Concentrations of contaminants were low in most houses, both with or without a wood-burning appliance. Globally, there was no consistent relationship between the presence of a wood-burning appliance and respiratory morbidity in residents. Nevertheless, residents who mentioned being exposed to fumes emitted by such an appliance reported more respiratory illnesses and symptoms. The presence of animals or molds, and keeping windows closed most of the time in winter were other factors associated with respiratory problems. We conclude that wood burning appears to be a respiratory health risk for occupants if the appliance is not maintained and used properly.

Excretion of volatile nitrosamines in a rural population in relation to food and drinking water consumption.

Urinary excretion of volatile nitrosamines was assessed in 59 non-smokers living in a rural county of Québec, Canada. Water and food intakes were measured by means of a 24-hour recall. Nitrates were analyzed in the tap water of all participants (geometric mean=2.0 mg nitrate-N/L) and dietary intakes of nitrate and vitamins C and E were estimated via a validated Canadian food database. Urine was collected over the same 24-hour period and analyzed for nitrates by hydrazine reduction and for volatile nitrosamines by gas-chromatography/mass spectrometry. N-Nitrosopiperidine (NPIP) was found in urine samples from 52 of the 59 subjects. Geometric mean of NPIP urinary excretion was 67 ng/day and maximum value was 1045 ng/day. No other volatile nitrosamine was detected. There was a correlation between urinary nitrate excretion and total nitrate intake (r=0.71, P < 0.001). However, no relationship was found between urinary NPIP excretion and either nitrate excretion, dietary or water nitrate intakes. NPIP excretion was significantly correlated to coffee intake (r=0.40, P=0.002) and this relation was not modified by vitamin intake. We conclude that nitrate intake is not related to nitrosamine excretion in this rural population. The influence of coffee consumption on NPIP excretion deserves further attention.

Sources of nitrate exposure in residents of rural areas in Quebec, Canada.

Nitrate exposure was investigated in a group of 187 people using well water and living in four areas of rural Quebec (Canada) with intensive agricultural activities. Nitrate intake was evaluated using a 24-h dietary recall and a food frequency questionnaire, in conjunction with a validated food database and measurements of nitrate concentrations in private wells. The total internal dose was estimated by means of the 24-h urinary nitrate excretion, while taking into account risk factors for endogenous nitrate formation. Mean (geometric) 24-h urinary nitrate excretion was 16.9 mg N for the 100 people with low groundwater contamination (mean nitrate concentration=0.18 mg N/l) and 23.3 mg N in the 87 individuals with moderate groundwater contamination (mean nitrate concentration=7.1 mg N/l). A multivariate analysis revealed that dietary nitrate intake during the last 24 h was the principal source of exposure, followed by water intake during the last 24 h. The Quetelet index was also a significant predictor of urinary excretion. The total predictive model explained only 29% of the variability in urinary nitrate excretion (R2=0.286). Neither the inflammatory status as indicated by elevated C reactive protein, the presence of Helicobacter pylori antibodies nor the occurrence of diarrhea during the last 24 h prior to urine collection were associated with urinary nitrate excretion. In conclusion, food and to a lesser extent water contribute to nitrate exposure in this rural setting with moderate water contamination. Better predictors of endogenous nitrate production are needed to improve our ability to model nitrate body burden and estimate associated health risks.

Susceptibility to infections and immune status in Inuit infants exposed to organochlorines.

We investigated whether organochlorine exposure is associated with the incidence of infectious diseases in Inuit infants from Nunavik (Arctic Quebec, Canada). We compiled the number of infectious disease episodes during the first year of life for 98 breast-fed and 73 bottle-fed infants. Concentrations of organochlorines were measured in early breast milk samples and used as surrogates to prenatal exposure levels. Immune system parameters were determined in venous blood samples collected from infants at 3, 7, and 12 months of age. Otitis media was the most frequent disease, with 80. 0% of breast-fed and 81.3% of bottle-fed infants experiencing at least one episode during the first year of life. During the second follow-up period, the risk of otitis media increased with prenatal exposure to p,p'-DDE, hexachlorobenzene, and dieldrin. The relative risk (RR) for 4- to 7-month-old infants in the highest tertile of p, p'-DDE exposure as compared to infants in the lowest tertile was 1. 87 [95% confidence interval (CI), 1.07-3.26]. The RR of otitis media over the entire first year of life also increased with prenatal exposure to p,p'-DDE (RR, 1.52; CI, 1.05-2.22) and hexachlorobenzene (RR, 1.49; CI, 1.10-2.03). Furthermore, the RR of recurrent otitis media ( [Greater/equal to] 3 episodes) increased with prenatal exposure to these compounds. No clinically relevant differences were noted between breast-fed and bottle-fed infants with regard to immunologic parameters, and prenatal organochlorine exposure was not associated with immunologic parameters. We conclude that prenatal organochlorine exposure could be a risk factor for acute otitis media in Inuit infants.