Air pollution and seasonal asthma during the pollen season. A cohort study in Puertollano and Ciudad Real (Spain)

BACKGROUND: Many studies have demonstrated a positive association between air pollutants and emergency visits for asthma. However, few studies have included pollen when analysing this relationship in mild-moderate asthmatic patients. OBJECTIVE: To determine the importance of the pollutants such as ozone (O(3)), particles (PM(10)), nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) in the clinical course of mild-moderate pollen-allergic asthmatic patients from two Spanish towns in La Mancha: Puertollano (high pollution levels) and Ciudad Real (low pollution levels). METHODS: We used a Poisson regression model to study a cohort of 137 patients from Puertollano and Ciudad Real during two pollen seasons (2000-2001) and analysed the relationship between air pollutant and pollen levels and daily symptoms, the medication used and peak-flow measurements. RESULTS: The number of asthma symptoms and the mean values of the PM(10), SO(2) and NO(2) levels were higher in Puertollano than in Ciudad Real. In Puertollano, the risk of asthma increased by 6% with a 3-day lag for PM(10), by 8% with a 3-day lag for O(3), by 4% with a 1-day lag for SO(2) and by 15% with a 3-day lag for O(3) when its values exceeded the health threshold (P < 0.05). CONCLUSIONS: The air pollution levels in Puertollano were associated with an increased risk of asthma symptoms in pollen-allergic asthmatic patients com pared with a similar group from Ciudad Real.     

Effects of air pollution on asthma hospitalization rates in different age groups in Hong Kong

AIMS: To assess the relationship between levels of ambient air pollutants and hospitalization rates for asthma in Hong Kong (HK). METHODS: This is a retrospective ecological study. Data of daily emergency hospital admissions to 15 major hospitals in HK for asthma and indices of air pollutants [sulphur dioxide (SO(2)), nitrogen dioxide (NO(2)), ozone (O(3)), particulates with an aerodynamic diameter of <10 microm particulate matter (PM(10)) and 2.5 microm (PM(2.5))] and meteorological variables from January 2000 to December 2005 were obtained from several government departments. Analysis was performed by the generalized additive models with Poisson distribution. The effects of time trend, season, other cyclical factors, temperature and humidity were adjusted. Autocorrelation and overdispersion were corrected. RESULTS: Altogether, 69 716 admissions were assessed. Significant associations were found between hospital admissions for asthma and levels of NO(2), O(3), PM(10) and PM(2.5). The relative risks (RR) for hospitalization for every 10 microg/m(3) increase in NO(2), O(3), PM(10) and PM(2.5) were 1.028, 1.034, 1.019 and 1.021, respectively, at a lag day that ranged from cumulative lag 0-4 to 0-5. In a multi-pollutant model, O(3) was significantly associated with increased admissions for asthma. The younger age group (0-14 years) tended to have a higher RR for each 10 microg/m(3) increase in pollutants than those aged 15-65 years. The elderly (aged >/=65 years) had a shorter 'best' lag time to develop asthma exacerbation following exposure to pollutants than those aged <65 years. CONCLUSION: Adverse effects of ambient concentrations of air pollutants on hospitalization rates for asthma are evident. Measures to improve air quality in HK are urgently needed.     

Residential outdoor air pollution and allergen sensitization in schoolchildren in Oslo, Norway

BACKGROUND: Epidemiological studies that have investigated the association between air pollution and atopy have found inconsistent results. Furthermore, often exposure to outdoor air pollution has had limited quality, and more individual exposure is needed. OBJECTIVE: To investigate the relations between early and lifetime exposure to residential outdoor air pollution and allergen sensitization in 9-10-year-old children in Oslo, Norway. METHODS: Sensitization to common allergens was measured by skin prick tests (SPTs), which were performed in 2244 children who had lived in Oslo since birth. Several definitions of positive SPT were used. Information on potential confounding variables was collected by a parental questionnaire. Exposure to outdoor air pollution was assessed by the EPISODE dispersion model, which calculates hourly concentrations of nitrogen dioxide (NO2), particulate matter (PM) with aerodynamic diameter <10 microm (PM10) and <2.5 microm (PM2.5), respectively. RESULTS: We found no associations between long-term air pollution exposure and sensitization to any allergen, any indoor or any pollen allergen. However, lifetime air pollution exposure was associated with sensitization to the house dust mite Dermatophagoides farinae. One interquartile increase of lifetime exposure to NO2, PM10 and PM2.5 was associated with 1.88 (adjusted odds ratio) (1.02, 3.47) [95% confidence interval (CI)], 1.61 (0.96, 2.72) and 1.46 (0.96, 2.22), respectively, for D. farinae. Lifetime exposure was also associated with sensitization to cat in a subpopulation. Both associations diminished after adjusting for a contextual socio-economic factor. CONCLUSION: Long-term exposure to traffic-related pollutants was generally not associated with allergen sensitization in 9-10-year-old Oslo children. However, lifetime exposure was associated with sensitization to D. farinae, and with sensitization to cat in a subpopulation, which may be explained by socio-economic confounding or multiple comparisons. The air pollution levels in Oslo may be too low to reveal associations with sensitization.     

Winter air pollution and disease parameters in advanced chronic obstructive pulmonary disease panels residing in Denver, Colorado

BACKGROUND: Ambient pollution might worsen chronic obstructive pulmonary disease (COPD). OBJECTIVE: We explored the associations of pollution to pulmonary function, rescue medication, and symptoms over 2 winters in 2 panels of subjects with advanced COPD in Denver, Colorado. METHODS: Subjects measured lung function and recorded symptoms and rescue medications. Daily ambient pollution concentrations for particulate matter (PM(10) and PM(2.5)), carbon monoxide (CO), and nitrogen dioxide (NO(2)) were obtained for Denver. Estimated effects of pollution on outcomes were derived for the same day and 1 and 2 days after pollution measurements (lags 0, 1, and 2, respectively). RESULTS: Sixteen (mean age, 65.8 years; mean FEV 1 , 42.3% of predicted value) and 18 (mean age, 67.4 years; mean FEV 1 , 39.4% of predicted value) subjects participated in the first and second winters, respectively. There were no differences in demographic or disease characteristics between the 2 panels. In the first winter no detrimental associations were found. In the second winter, however, there were significant detrimental associations of CO in the morning and PM(10), CO, and NO(2) in the evening, increasing medication use at lag 0. Total symptom score increased at lag 0 with NO(2). The concentrations of particulates were increased in the second winter compared with in the first winter, and this winter was colder and more humid. CONCLUSIONS: In the second winter, subjects with severe COPD had worse lung function at lags 0 and 1 and increased rescue medication at lag 0 with increases in ambient air pollution. The effects of pollution varied between the 2 winters, perhaps related to levels of pollution and weather patterns. Significant effects were seen despite ambient pollution levels that conformed to US Environmental Protection Agency standards.     

Long-term exposure to background air pollution related to respiratory and allergic health in schoolchildren

BACKGROUND: The impact of air pollution on asthma and allergies still remains a debate. OBJECTIVE: Our cross-sectional study was intended to analyse the associations between long-term exposure to background air pollution and atopic and respiratory outcomes in a large population-based sample of schoolchildren. METHODS: Six thousand six hundred and seventy-two children aged 9-11 years recruited from 108 randomly schools in six French cities underwent a clinical examination including a skin prick test (SPT) to common allergens, exercise-induced bronchial reactivity (EIB) and skin examination for flexural dermatitis. The prevalence of asthma, allergic rhinitis (AR) and atopic dermatitis was assessed by a standardized health questionnaire completed by the parents. Three-year-averaged concentrations of air pollutants (NO2, SO2, PM10 and O3) were calculated at children' schools using measurements of background monitoring stations. RESULTS: After adjusting for confounders, EIB, lifetime asthma and lifetime AR were found to be positively related to an increase in the exposure to SO2, PM10 and O3. The adjusted odds ratios (aOR) per increase of 5 microg/m3 of SO2 was 1.39 (95% confidence interval (CI)=1.15-1.66) for EIB and 1.19 (1.00-1.41) for lifetime asthma. The aOR for lifetime AR per increase of 10 microg/m3 of PM10 was 1.32 (CI=1.04-1.68). Moreover, SPT positivity was associated with O3 (aOR=1.34; CI=1.24-1.46). Associations with past year symptoms were consistent, even if not always statistically significant. Results persisted in long-term resident (current address for at least 8 years) children. However, no consistent positive association was found with NO2. CONCLUSIONS: A moderate increase in long-term exposure to background ambient air pollution was associated with an increased prevalence of respiratory and atopic indicators in children.     

Temporal relationship between air pollution and hospital admissions for asthmatic children in Hong Kong

BACKGROUND: Many epidemiological studies have shown positive association between respiratory health and current levels of outdoor air pollution in Europe and America. OBJECTIVE: The aim of this study was to investigate the association between air pollution and the number of childhood admissions for asthma in Hong Kong. METHODS: Daily counts of childhood admission for asthma to a large teaching Hospital were obtained from the computerized database for the period 1993-1994. A Poisson regression allowing for seasonal patterns and meteorological conditions was used to assess the associations between the number of Hospital admissions and the three pollutants: nitrogen dioxide, sulphur dioxide and inhalable particles (measured as PM10, particles < 10 microm in aerodynamic diameter). RESULTS: A total of 1217 children under 15 years of age were admitted for asthma during the study period. The calculated annual hospitalization rates were 283 and 178 per 100 000 for boys and girls, respectively. The mean PM10, NO2 and SO2 levels were 44.1 microg/m3, 43.3 microg/m3, and 12.2 microg/m3, respectively. Daily admission for asthma increased significantly with increasing ambient level of nitrogen dioxide (relative risk (RR) = 1.08 per 10 microg/m3 increase), sulphur dioxide (RR = 1.06) and inhalable particles (RR = 1.03). No association was found between hospital admission and humidity, temperature or atmospheric pressure. CONCLUSION: This is the first daily time series study of childhood admissions for asthma and air pollution in Hong Kong. The results support that current levels of air pollution contribute to the respiratory morbidity in asthmatic children in Hong Kong.     

Association between air pollution and asthma admission among children in Hong Kong

OBJECTIVE: To examine the association of air pollutants with hospital admission for childhood asthma in Hong Kong. METHODS: Data on hospital admissions for asthma, influenza and total hospital admissions in children aged < or =18 years at all Hospital Authority hospitals during 1997-2002 were obtained. Data on daily mean concentrations of particles with aerodynamic diameter <10 microm (i. e. PM10) and <2.5 microm (i. e. PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3) and data on meteorological variables were associated with asthma hospital admissions using Poisson's regression with generalized additive models for correction of yearly trend, temperature, humidity, day-of-week effect, holiday, influenza admissions and total hospital admission. The possibility of a lag effect of each pollutant and the interaction of different pollutants were also examined. RESULTS: The association between asthma admission with change of NO2, PM10, PM2.5 and O3 levels remained significant after adjustment for multi-pollutants effect and confounding variables, with increase in asthma admission rate of 5.64% (3.21-8.14) at lag 3 for NO2, 3.67% (1.52-5.86) at lag 4 for PM10, 3.24% (0.93-5.60) at lag 4 for PM2.5 and 2.63% (0.64-4.67) at lag 2 for O3. Effect of SO2 was lost after adjustment. CONCLUSION: Ambient levels of PM10, PM2.5) NO2 and O3 are associated with childhood asthma hospital admission in Hong Kong.     

Modifications of Phleum pratense grass pollen allergens following artificial exposure to gaseous air pollutants (O(3), NO(2), SO(2))

BACKGROUND: Air pollution is frequently proposed as a potential cause of the increased incidence of allergy in industrialised countries. Our objective was to investigate the impact of the major gaseous air pollutants on grass pollen allergens. METHODS: Timothy grass pollen was exposed to ozone (O(3)), nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) alone or in combination. Allergen contents were analysed by 2-dimensional immunoblot using grass pollen-sensitive patient sera. RESULTS: For O(3)-treated pollen, immunoblotting showed an acidification of allergens Phl p 1b, Phl p 4, Phl p 5 and Phl p 6 and an IgE recognition decrease in Phl p 1, Phl p 2, Phl p 6 and Phl p 13. NO(2) exposure induced a decrease in Phl p 2, Phl p 5b and Phl p 6 recognition, and SO(2) treatment induced a decrease in Phl p 2, Phl p 6 and Phl p 13 recognition. Moreover, samples treated with a mix of NO(2)/O(3) or NO(2)/SO(2) showed a higher decrease in allergen content, compared with samples treated with only one pollutant. The O(3) acidification was also observed with the NO(2)/O(3) mix. CONCLUSION: Exposure of pollen to gaseous pollutants induced a decrease in allergen detection in pollen extracts. This decrease could be due to a mechanical loss of allergens from the altered pollen grains and/or post-translational modifications affecting allergen recognition by IgE.     

In vitro exposure to carbon dioxide induces oxidative stress in human peritoneal mesothelial cells

BACKGROUND: The objective of this study was to verify whether in vitro exposure of human peritoneal mesothelial cells to carbon dioxide (CO(2)) influences the levels of 8-isoprostaglandin F(2alpha) (8-iso-PGF(2alpha)), a marker of oxidative stress. METHODS: Mesothelial cells were exposed to either: (i). 100% CO(2) for 4 h; (ii). 100% helium (an alternative gas with which to create hypoxic conditions) for 4 h; (iii). 100% CO(2) for 24 h; or (iv). standard conditions (control). After gas exposure, mesothelial cells were returned to standard conditions and harvested immediately (T(0)), and at 1-(T(1)) and 3 (T(3)) h afterwards. Cell viability and culture medium pH were monitored throughout the experiments. 8-iso-PGF(2alpha) was assayed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Exposure to CO(2) decreased the culture medium pH whereas helium increased the pH. 8-iso-PGF(2alpha) levels in all treated groups were significantly higher than in the control group: in the 4 h CO(2) group at T(1); in the 24 h CO(2) group at T(0) and T(1); and in the 4 h helium group at T(0), T(1) and T(3). 8-iso-PGF(2alpha) levels following 4 h CO(2) exposure were significantly lower than after 24 h CO(2) exposure at T(1), and lower than following 4 h helium exposure at all time points. CONCLUSIONS: Exposure to both CO(2) and helium induces oxidative stress in mesothelial cells. Hypoxia-reoxygenation may play a role in this process.     

Factors influencing the obstetric and perinatal outcome after oocyte donation

BACKGROUND: We evaluated interactions between perinatal outcome after oocyte donation and various maternal factors. METHODS: The study included 134 parturients after oocyte donation. Data were collected from medical files and personal interviews. Stepwise logistic regression analyses were used to evaluate associations between perinatal outcomes and selected maternal variables. RESULTS: Fifty percent of the women were >43 years old, 30.6% were >45 years and 67.9% were nulliparous. The rates of pregnancy induced hypertension (PIH), gestational diabetes and first and second trimester vaginal bleeding (STB) were 27.6, 23.9, 43.3 and 6% respectively, while 72% had Caesarean deliveries. The rates of preterm (PD), low birth weight (LBW), small for gestational age (SGA) deliveries and major malformations were respectively 14.9, 14.9, 7.6 and 2.2%. Using a logistic regression, PD was significantly associated with PIH, STB and maternal smoking. LBW deliveries were significantly associated with PIH, STB, nulliparity and maternal smoking. SGA babies were significantly associated with PIH. These perinatal outcomes were not associated with advanced maternal age or ovarian failure. CONCLUSIONS: There is a high risk of obstetric complications in singleton oocyte donation pregnancies, but the perinatal outcomes are favourable. Patients should be counselled about these risks and monitored for these complications during pregnancy.     

The balance between stress and personal capital during pregnancy and the relationship with adverse obstetric outcomes: findings from the 2007 Los Angeles Mommy and Baby (LAMB) study

Stress during pregnancy is a salient risk factor for adverse obstetric outcomes. Personal capital during pregnancy, defined as internal and social resources that help women cope with or decrease their exposure to stress, may reduce the risk of poor obstetric outcomes. Using data from the 2007 Los Angeles Mommy and Baby study (N?=?3,353), we examined the relationships between the balance of stress and personal capital during pregnancy, or the stress-to-capital ratio (SCR), and adverse obstetric outcomes (i.e., pregnancy complications, preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA)). Women with a higher SCR (i.e., greater stress relative to personal capital during pregnancy) were significantly more likely to experience at least one pregnancy complication, PTB, and lower gestational age, but not LBW or SGA. Accounting for pregnancy complications completely mediated the association between the SCR and PTB. Our findings indicate that experiencing greater stress relative to personal capital during pregnancy is associated with an increased risk for pregnancy complications, PTB, and lower gestational age and that pregnancy complications may be a mechanism by which the SCR is related to adverse obstetric outcomes.     

Acute effect of air pollution on respiratory complaints,exhaled NO and biomarkers in nasal lavages of allergic children during the pollen season

During 2 months of the pollen season, the acute and putative adjuvant effect of traffic-related air pollution on respiratory health was investigated in children sensitised to grass pollen or house dust mite (HDM). Respiratory complaints were objectified via measurement of exhaled NO and inflammatory mediators in nasal lavage (NAL). During the study children, skin prick negative (n = 31) or positive to grass pollen (n = 22), HDM (n = 34) or grass pollen + HDM (n = 32), kept a daily diary on respiratory symptoms, and NAL and exhaled air was sampled twice a week. The level of air pollutants and pollen was monitored continuously. Like children sensitised to HDM, those sensitised to pollen reported respiratory complaints (shortness of breath, itchy eyes or blocked nose) more frequently than non-sensitised children during (but not before) the pollen season; the respiratory complaints of sensitised children were independent of the pollen level. In addition, exposure to increased levels of PM(10) induces 'shortness of breath' in pollen- and HDM-sensitised children, whereas ozone induces a blocked nose in HDM-sensitised children. Combined exposure to PM(10) + pollen and O(3) + pollen induces a blocked nose in both HDM-sensitised children and children sensitised to pollen + HDM. Significant positive associations were found between eNO and the levels of NO(2), CO, PM(2.5) and pollen in both sensitised and non-sensitised children. At the start of the pollen season, the NAL concentration of eosinophils and ECP in pollen-sensitised children was increased compared to winter, but their levels were not further affected by increased exposure to pollen or air pollution. In conclusion, during the pollen season, sensitised children continuously report a high prevalence of respiratory complaints which coincides with increased levels of upper and lower airway inflammatory markers. No additional pro-inflammatory effect of air pollution was observed, which indicates that air pollution does not facilitate allergen-induced inflammatory responses.     

The relationship between low level nitrogen dioxide exposure and child lung function after cold air challenge

BACKGROUND: Nitrogen dioxide (NO(2)) or home gas appliance use has been inconsistently associated with adverse respiratory outcomes in childhood. OBJECTIVES: (i) To examine the contribution of home gas appliance type and personal NO(2) exposure. (ii) To examine the relationship between NO(2) exposure and child lung function and respiratory history. (iii) To assess whether these relationships vary by house dust mite sensitization status. METHODS: A cross-sectional survey of 344 children (71% of the eligible group) with a mean age of 9.1 years from four randomly selected schools in the Australian Capital Territory from July to September 1999. Study measurements included a parental questionnaire, NO(2) exposure by passive gas samplers, skin prick testing for 10 aeroallergens and lung function at rest and after cold air challenge. RESULTS: Total NO(2) exposure was low with a mean concentration of 10.1 ppb. No associations were found between NO(2) exposure or gas appliance use and asthma, wheeze or baseline lung function. Personal NO(2) exposure was associated with a reduction in forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) after cold air challenge (adjusted difference - 0.12% (- 0.23% to - 0.01%) per 1 ppb increase). After exclusion of children who had home heating changed because of asthma, gas heater use was also significantly associated with a reduction in this measure (adjusted difference - 2.0% (- 3.7% to - 0.2%)). There was some evidence that these reductions were greater among the non-mite-sensitized children. CONCLUSIONS: The effect of low-level NO(2) exposure on these respiratory outcomes was not marked. The possible effect of low-level NO(2) exposure on non-specific bronchial reactivity requires confirmation. Future studies on NO(2) and respiratory health should include measures of house dust mite sensitization and bronchial hyper-responsiveness.     

空气中SO_2和NO_2对糖尿病患者影响的病例交叉研究

目的采用病例交叉设计研究空气污染物(SO_2、NO_2和PM10)对糖尿病患者健康结局的影响。方法收集南京市2008年1月1日至2011年12月31日空气污染物数据、气象数据以及糖尿病患者死亡数据。用双向病例交叉设计,调整气象因素影响后,研究空气中SO_2、NO_2、PM10与糖尿病患者死亡之间的关系。同时,对年龄、性别和季节因素进行分层分析。结果空气中SO_2、NO_2平均每增加10μg/m~3,糖尿病患者死亡的OR值及其95%可信区间(95%CI)分别为1.031(1.005,1.058)和1.042(1.012,1.074);空气污染物中NO_2和SO_2对老年人影响较大,且在冬季存在显著的有害效应。结论空气中NO_2和SO_2可能对糖尿病患者死亡产生影响。     

Genetic variation in biotransformation enzymes,air pollution exposures,and risk of spina bifida

Spina bifida is a birth defect characterized by incomplete closure of the embryonic neural tube. Genetic factors as well as environmental factors have been observed to influence risks for spina bifida. Few studies have investigated possible gene‐environment interactions that could contribute to spina bifida risk. The aim of this study is to examine the interaction between gene variants in biotransformation enzyme pathways and ambient air pollution exposures and risk of spina bifida. We evaluated the role of air pollution exposure during pregnancy and gene variants of biotransformation enzymes from bloodspots and buccal cells in a California population‐based case‐control (86 cases of spina bifida and 208 non‐malformed controls) study. We considered race/ethnicity and folic acid vitamin use as potential effect modifiers and adjusted for those factors and smoking. We observed gene‐environment interactions between each of the five pollutants and several gene variants: NO (ABCC2), NO₂ (ABCC2, SLC01B1), PM₁₀ (ABCC2, CYP1A1, CYP2B6, CYP2C19, CYP2D6, NAT2, SLC01B1, SLC01B3), PM_2.5 (CYP1A1 and CYP1A2). These analyses show positive interactions between air pollution exposure during early pregnancy and gene variants associated with metabolizing enzymes. These exploratory results suggest that some individuals based on their genetic background may be more susceptible to the adverse effects of pollution.     

The relationship of air pollution to the prevalence of allergic diseases in Taichung and Chu-Shan in 2002.

This study was conducted in order to determine the relationship between air pollution and the varying prevalence of allergic diseases in the city of Taichung and the rural town of Chu-Shan. We used questionnaires to screen children aged from 7 to 15 years in Taichung and Chu-Shan and compared the results from these 2 areas with the factors related to air pollution. The study included 11,580 children in Taichung and 2621 children in Chu-Shan. In Taichung, the prevalence of asthma was 7.0%, of allergic rhinitis 27.6% and of atopic dermatitis 3.4%. In Chu-Shan, the prevalence of asthma was 5.6%, of allergic rhinitis 21.8% and of atopic dermatitis 3.3%. We also collected data on the concentration of air pollutants in the 2 areas over a 1-year period from January to December 2001 and compared the average annual concentrations of various pollutants. Compared with Chu-Shan, Taichung had higher air concentrations of nitric oxide (NO; 11.47 +/- 4.75 vs 5.07 +/- 2.81 ppb), carbon monoxide (CO; 0.78 +/- 0.19 vs 0.59 +/- 0.12 ppm), nitrogen dioxide (NO(2); 24.99 +/- 6.8 vs 21.45 +/- 7.87 ppb) and sulfur dioxide (SO(2); 2.58 +/- 1.0 vs 2.44 +/- 0.88 ppb). Student's t test results showed that CO and NO were related significantly to the prevalence of allergic disease (p<0.005). The prevalence of both asthma and allergic rhinitis is higher in Taichung than in Chu-Shan, a finding that could be related to higher levels of some air pollutants in the urban location.     

Maternal early second trimester pregnancy weight in relation to birth outcome among Bengalee Hindus of Kolkata, India

OBJECTIVE: The study examined to what degree maternal early second trimester pregnancy weight is useful and efficient in predicting birth outcome of Bengalee women. SUBJECTS AND METHODS: The cross-sectional retrospective study was conducted in a government general hospital in South Kolkata, India. This hospital serves the needs of people belonging to lower and lower middle class socio-economic groups. Data were collected by one-to-one interview for confirmation of age, history of last menstrual period (LMP) including medical disorders. Mother's weight was recorded at 14-18 weeks of pregnancy from the history of LMP. Birth weight was measured within 24h of delivery and gestational age was assessed by Ballard's method using newborn physical and neurological maturity scoring. Of the 331 Bengalees, 295 mother-baby pairs met the recruitment criteria and were included in this study. RESULT: Mean +/- SD maternal early second trimester pregnancy weight and birth weight were 45.9+/-7.0kg and 2612+/-371g, respectively. The difference in mean weight (3.74kg) between mothers who delivered low birth weight (LBW) and normal birth weight (NBW) babies was statistically significant (t = 4.497, p < 0.001). Overall, the prevalence of LBW was nearly 34%. A higher incidence of LBW and lower mean birth weight was observed in first quartile or low weight (< or =40 kg) mothers. The rate of LBW decreased (chi2 =14.47, p<0.01) and mean birth weight increased significantly with increasing maternal weight (F=9.218, p<0.001). Risk ratio (RR) for LBW, intrauterine growth retardation (IUGR) and preterm birth in low weight (first quartile or <40.0 kg) mothers were 2.72 (95% confidence interval (CI): 1.45-5.10), 3.54 (95% CI: 1.17-10.74) and 1.97 (95% CI: 0.56-6.90), respectively, compared with heavier (>50.0kg) mothers. Finally, the present data showed that the maternal weight of <46.0 kg is the best cut-off for detecting LBW with 66% sensitivity and 75% negative predictive power. CONCLUSION: The findings suggest a positive association between maternal early second trimester pregnancy weight and birth outcome. The present study provided an efficient cut-off point for detecting LBW. Antenatal caregivers in health institutions and community health workers in the field can use this cut-off value for screening pregnant women at early second trimester.     

空气污染对胎儿生长发育的影响及作用机制

近十年来,已经有了越来越多关于空气污染与胚胎发育影响的研究报告。流行病学观察和实验研究等均显示,产前暴露于空气污染与低出生体重（LBW）、早产（PTB）、胎儿宫内生长受限（IUGR）、先天性缺陷、胎肺发育延迟、死胎、死产和新生儿死亡等不良妊娠结局有关。本文回顾空气污染物胎儿生长发育的影响及其作用机制的研究进展。     

Crown-Rump Length Measured in the Early First Trimester as a Predictor of Low Birth Weight

The aim of this study is to assess the association between crown-rump length (CRL) measured before the 10th gestational week and birth weight. Results from 316 transvaginal ultrasonography scans at the 46th, 53rd, 60th, 67th, and 74th days of pregnancy were compared in low birth weight (LBW) versus normal birth weight groups. A positive correlation between CRL and birth weight was observed when CRL was measured at days 60, 67, and 74. CRL measured on the 67th day of pregnancy was significantly smaller in the LBW group than in the normal birth weight group. A cut-off value of CRL=26.5 mm measured at day 67 has the highest power to predict LBW.     

Maternal early second trimester pregnancy weight in relation to birth outcome among Bengalee Hindus of Kolkata,India

Objective: The study examined to what degree maternal early second trimester pregnancy weight is useful and efficient in predicting birth outcome of Bengalee women.

Subjects and methods: The cross-sectional retrospective study was conducted in a government general hospital in South Kolkata, India. This hospital serves the needs of people belonging to lower and lower middle class socio-economic groups. Data were collected by one-to-one interview for confirmation of age, history of last menstrual period (LMP) including medical disorders. Mother's weight was recorded at 14–18 weeks of pregnancy from the history of LMP. Birth weight was measured within 24?h of delivery and gestational age was assessed by Ballard's method using newborn physical and neurological maturity scoring. Of the 331 Bengalees, 295 mother–baby pairs met the recruitment criteria and were included in this study.

Result: Mean?±?SD maternal early second trimester pregnancy weight and birth weight were 45.9?±?7.0?kg and 2612?±?371?g, respectively. The difference in mean weight (3.74?kg) between mothers who delivered low birth weight (LBW) and normal birth weight (NBW) babies was statistically significant (t?=?4.497, p?<?0.001). Overall, the prevalence of LBW was nearly 34%. A higher incidence of LBW and lower mean birth weight was observed in first quartile or low weight (≤40?kg) mothers. The rate of LBW decreased (χ²?=?14.47, p?<?0.01) and mean birth weight increased significantly with increasing maternal weight (F?=?9.218, p?<?0.001). Risk ratio (RR) for LBW, intrauterine growth retardation (IUGR) and preterm birth in low weight (first quartile or <40.0?kg) mothers were 2.72 (95% confidence interval (CI): 1.45–5.10), 3.54 (95% CI: 1.17–10.74) and 1.97 (95% CI: 0.56–6.90), respectively, compared with heavier (>50.0?kg) mothers. Finally, the present data showed that the maternal weight of <46.0?kg is the best cut-off for detecting LBW with 66% sensitivity and 75% negative predictive power.

Conclusion: The findings suggest a positive association between maternal early second trimester pregnancy weight and birth outcome. The present study provided an efficient cut-off point for detecting LBW. Antenatal caregivers in health institutions and community health workers in the field can use this cut-off value for screening pregnant women at early second trimester.