Childhood asthma and extreme values of body mass index: the Harlem Children's Zone Asthma Initiative.

To examine the association between body mass index (BMI) percentile and asthma in children 2-11 years of age, we performed a cross-sectional analysis of 853 Black and Hispanic children from a community-based sample of 2- to 11-year olds with measured heights and weights screened for asthma by the Harlem Children's Zone Asthma Initiative. Current asthma was defined as parent/guardian-reported diagnosis of asthma and asthma-related symptoms or emergency care in the previous 12 months. Among girls, asthma prevalence increased approximately linearly with increasing body mass index (BMI) percentile, from a low of 12.0% among underweight girls (BMI 95th percentile). After adjusting for age, race/ethnicity, and household smoking, among girls, having asthma was associated with being at risk for overweight (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.4-5.0) and being overweight (OR, 2.1; 95% CI, 1.2-3.8) compared to normal weight; among boys, having asthma was associated both with overweight (OR, 2.4; 95% CI, 1.4-4.3) and with underweight (OR, 2.9; 95% CI, 1.1-7.7). Large, prospective studies that include very young children are needed to further explore the observed association between underweight and asthma among boys. Early interventions that concomitantly address asthma and weight gain are needed among pre-school and school-aged children.

The epidemiology of asthma during pregnancy: prevalence, diagnosis, and symptoms.

We demonstrated that asthma remains a common condition among pregnant women and that the prevalence of self-reported asthma in the United States is between 8.4% and 8.8%. In addition, approximately 4.1% of all pregnant women experienced an asthma attack in the previous year. Prevalence rates in other countries seem to be higher or substantially lower; however, further characterization of international trends using nationally representative data is needed. Data from a large prospective cohort study in the northeastern United States and national data demonstrate continued opportunities for population-level improvement in well-managed asthma during pregnancy. Finally, asthma diagnosis and asthma control seem to differ by population characteristics (eg, age, race/ethnicity, socio-economic status), and further research and clinical involvement are needed to ad-dress potentially systematic variation in reporting and management of the disease.

Effect of fetal sex on airway lability in pregnant women with asthma.

The authors investigated the association between sex of the fetus and maternal airway lability among pregnant women with asthma. Data were prospectively collected among 702 pregnant women with a diagnosis of asthma who were recruited in southern New England between 1997 and 2000 and followed through pregnancy. Peak expiratory flow lability, defined as percent daily maximum minus the minimum divided by the mean, was assessed at enrollment and at 21, 29, and 37 weeks' gestation. There was a -9.9 percent (95 percent confidence interval: -19.4, -0.4) difference in airway lability observed between women carrying female fetuses and those carrying male fetuses. This difference persisted throughout pregnancy. Among pregnant asthmatic women, carrying a female fetus is associated with worse maternal asthma, as assessed by greater airway lability, than is carrying a male fetus.

Effect of pregnancy and stage of pregnancy on asthma severity: a systematic review.

Although pregnancy is purported to affect maternal asthma, the literature has not been reviewed systematically. The purpose of this systematic review was to determine, among pregnant women with asthma, whether pregnancy and stage of pregnancy influence maternal asthma severity. Six electronic databases were searched in January 2003 for prospective studies of currently asthmatic, pregnant women who were enrolled before the third trimester and assessed with objective measures of asthma severity or validated severity scales. Three studies reported 54 pregnant women with asthma who met the inclusion criteria. The most valid study indicated that bronchial hyperresponsiveness to methacholine improved between preconception and pregnancy in 69% of the women, although it deteriorated in 31% of the women. Further, this improvement peaked in the second trimester, reverted after delivery, and was greatest among those women who were most hyperresponsive initially. Lung function also showed a trend towards improvement during pregnancy that was not significant. Large, well-conducted population-based studies that explore different aspects of asthma severity are needed to substantiate these preliminary results.

Asthma prevalence among pregnant and childbearing-aged women in the United States: estimates from national health surveys.

PURPOSE: Asthma is a major complication of pregnancy, but there are currently no reliable national estimates for the United States of asthma prevalence in pregnancy or in the childbearing years. METHODS: The prevalence of asthma among pregnant women and all childbearing-aged women was estimated and examined by age group using the National Health Interview Survey (NHIS), 1997-2000, the Behavioral Risk Factor Surveillance System (BRFSS), 2000-2001, and the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. Time trends were explored using NHANES II (1976-1980) and NHANES III (1988-1994). RESULTS: Asthma was estimated to affect from 88,573 to 190,650 pregnant women between 1997 and 2001, or approximately 3.7% to 8.4% of pregnant women in the United States. A slightly lower estimate of 3.2% was obtained for the period between 1988 and 1994. Among adult women of childbearing age, a two-fold increase in asthma from 2.9% to 5.8% occurred between 1976-1980 and 1988-1994. Among women aged 18 to 24, the increase was three-fold, from 1.8% to 6.0%. CONCLUSION: The prevalence of asthma during pregnancy may be higher than previously estimated and appears to be continuing to increase.