The predictive value of increased sentinel lymph node volume in breast cancer.

BACKGROUND: Breast cancer sentinel lymph nodes (SLNs) with metastases (mets) are often palpably enlarged. We hypothesized that the volume of the SLN and the size of mets are directly related. SLNs harboring mets are often firm, with increased intra-nodal pressure (INP), and we hypothesized that SLN volume, as well as INP, would correlate directly with SLN metastasis size. METHODS: The SLN volume, INP and met size were measured in 296 SLNs and compared using linear regression analysis. The SLNs were subsequently grouped based upon pN stage. SLN INP and volume were compared between these resultant groups. RESULTS: Increased SLN volume significantly predicted increased SLN met size on univariate and multivariate analysis (p = 0.001 and p = 0.011, respectively). SLN met size predicted increased SLN INP on both univariate and multivariate analysis (both p = 0.001). SLN volume only significantly correlated with increased SLN INP on univariate analysis (p = 0.001). On subgroup analysis of nodal disease, pN1/2/3 nodes (SLN met sizes >2 mm) were significantly larger (p = 0.039 and p = 0.003, respectively) than pN0 and pN1(mi) nodes, and had significantly increased INP (all p = 0.001) as compared to pN0, pN0(i+), and pN1(mi) nodes. CONCLUSIONS: SLN volume and INP increased with increasing SLN met size. The threshold met size for this increase was >2 mm (pN1 disease).

Are cats and dogs the major source of endotoxin in homes?

UNLABELLED: Previous studies have suggested that exposure to cats and dogs during early childhood reduces the risk of allergic disease, possibly by increasing home endotoxin exposure. This study asked the question of whether cats and dogs are the dominant influence on dust endotoxin concentrations in homes after considering other variables reportedly associated with endotoxin. The presence of cats or dogs in homes, household and home characteristics, and dust endotoxin concentrations from 5 locations were assessed in 966 urban and suburban homes. Whether considered together as pets or as cats and dogs separately, the presence of cats and dogs significantly contributed to living room and bedroom floor endotoxin concentrations, but not to bed endotoxin concentrations. However, the two variables consistently related to endotoxin in all home sites were the home occupant density (occupants/room) and cleanliness of the home. Our data suggest that reducing occupant density and improving home cleanliness would reduce home endotoxin concentrations more than removing pet cats or dogs from the home. PRACTICAL IMPLICATIONS: Many studies have shown that early childhood exposure to indoor cats or dogs is associated with a reduced risk of later allergic disease and asthma. An important question is whether alteration in allergic risk associated with cat and dog exposure results from increased endotoxin exposure or from some other associated exposure. Our findings show that cats and dogs are not the dominant source of endotoxin in homes; rather, the density of human occupation and poor cleaning contribute more consistently to higher home endotoxin concentrations especially in the beds.

Factors associated with nonresponse to a computer-tailored asthma management program for urban adolescents with asthma.

BACKGROUND: The ability to identify potentially resistant participants early in the course of an intervention could inform development of strategies for behavior change and improve program effectiveness. OBJECTIVE: The objective of this analysis was to identify factors related to nonresponse (i.e., lack of behavior change) to an asthma management intervention for urban teenagers. The intervention targeted several behaviors, including medication adherence, having a rescue inhaler nearby, and smoking. METHODS: A discriminate analysis was conducted using data from a randomized trial of the intervention. Included in this analysis are participants who reported a physician diagnosis of asthma, completed a baseline questionnaire, were randomized to the treatment group, completed >or=2 of 4 educational sessions, and completed >or=2 of 3 follow-up questionnaires. Ninety students met criteria for inclusion in this subgroup analysis. RESULTS: In logistic regression models for medication adherence, nonresponse was related to low baseline asthma self-regulation, odds ratio = 3.6 (95% confidence interval = 1.3-9.5). In models for having an inhaler nearby, nonresponse was related to low baseline self-regulation and to rebelliousness, OR = 4.7 (1.6-13.2) and 5.6 (1.7-18.0), respectively. Nonresponse to smoking messages was related to rebelliousness, low emotional support, and low religiosity, ORs = 7.6 (1.8-32.3), 9.5 (1.4-63.5), and 6.6 (1.5-29.8) respectively. CONCLUSIONS: Certain variables had the ability to discriminate the likelihood of response from that of nonresponse to an asthma program for urban, African American adolescents with asthma. These variables can be used to identify resistant subgroups early in the intervention, allowing the application of specialized strategies through tailoring. These types of analyses can inform behavioral interventions.

Gender differences in the association of overweight and asthma morbidity among urban adolescents with asthma.

Asthma and obesity disproportionately affect US African-American youth. Among youth with asthma, obesity has been associated with poor control. The impact of gender on this association is unclear. We examined these relationships in a sample of urban, African-American adolescents with asthma. Questionnaires were used to identify high school students with asthma, and to examine the association of body mass index (BMI) to asthma morbidity, by gender. Of 5967 students completing questionnaires, 599 (10%) met criteria for asthma and 507 had data sufficient for inclusion in further analyses (46% male, mean age = 15.1 yr). Univariately, BMI > 85th percentile was significantly related only to reported emergency department visits (ED) and school days missed for any reason, Odds Ratio (95%Confidence Interval) = 1.7(1.1-2.7), p = 0.01 and 1.8(1.1-3.0), p = 0.01, respectively. A significant gender-BMI interaction (p < 0.05) was observed in multivariate models for ED visits, hospitalizations and school days missed for asthma. In gender-specific models, adjusted Risk Ratios for BMI > 85th and ED visits, hospitalizations, and school days missed because of asthma were 1.7(0.9-3.2), 6.6(3.1-14.6) and 3.6(1.8-7.2) in males. These associations were not observed in females. Gender modifies the association between BMI and asthma-related morbidity among adolescents with asthma. Results have implications for clinical management as well as future research.

Estimating post-traumatic stress disorder in the community: lifetime perspective and the impact of typical traumatic events.

BACKGROUND: Community surveys have assessed post-traumatic stress disorder (PTSD) in relation to traumatic events designated by respondents as the worst they have ever experienced. An assessment of PTSD in relation to all reported traumas would impose too great a burden on respondents, a considerable proportion of whom report multiple traumas. The 'worst event' method is efficient for identifying persons with PTSD, but may overestimate the conditional probability of PTSD associated with the entire range of PTSD-level traumas. In this report, we evaluate this potential bias. METHOD: The Detroit Area Survey of Trauma (n = 2181) estimated the PTSD risk from two samples of traumas: (1) a representative sample of traumas formed by selecting a random trauma from each respondent's list of traumas; and (2) traumas designated by respondents as the worst (the standard method). RESULTS: Both estimation methods converged on key findings, including identifying trauma types with the highest probability of PTSD and sex differences in the risk of PTSD. Compared to the random events, the 'worst event' method yielded a moderately higher conditional probability for PTSD (0.136 v. 0.092). The bias was due almost entirely to the deviation of the distribution of the worst events from expected values, if all event types had equal prior selection probabilities. Direct adjustment, setting the distribution equal to expected values and applying the observed probabilities of PTSD associated with individual event types brought the estimate close to the unbiased estimate, based on the randomly selected traumas. CONCLUSIONS: Only the 'worst event' method can be used as a short-cut to assessing all traumas. The bias in the estimated risk of PTSD is modest and is attenuated by direct adjustment.

Stability and change in children's intelligence quotient scores: a comparison of two socioeconomically disparate communities.

The authors estimated the influence of familial factors and community disadvantage on changes in children's intelligence quotient (IQ) scores from age 6 years to age 11 years. Data were obtained from a longitudinal study of the neuropsychiatric sequelae of low birth weight in two socioeconomically disparate, geographically defined communities in the Detroit, Michigan, metropolitan area. Representative samples of low birth weight and normal birth weight children from the City of Detroit (urban) and nearby middle-class suburbs (suburban) were assessed at age 6 years (in 1990-1992) and age 11 years (in 1995-1997) (n = 717). Children's IQs were measured using the Wechsler Intelligence Scale for Children-Revised. The familial factors considered included maternal IQ, education, and marital status. Multiple regression analysis applying generalized estimating equations was used. The IQs of urban children, regardless of birth weight, declined from age 6 years to age 11 years. The downward shift increased by 50% the proportion of urban children scoring 1 standard deviation below the standardized IQ mean of 100. A negligible change was observed in suburban children. Maternal IQ, education, and marital status and low birth weight predicted IQ at age 6 years but were unrelated to IQ change. Growing up in a racially segregated and disadvantaged community, more than individual and familial factors, may contribute to a decline in IQ score in the early school years.

Occupational categories at risk for Parkinson's disease.

BACKGROUND: The etiology of Parkinson's disease (PD) is considered to have a strong environmental component, but relatively few studies have investigated the potential association between occupation and the disease. METHODS: In a population-based case-control study, we collected comprehensive occupational histories from all study participants, 144 case and 464 control subjects. RESULTS: Chi-square analysis revealed that working in an agricultural occupation increased estimated PD risk (OR = 1.74; 95% CI = 0.85, 3.60). In contrast, a history of ever working in a service occupation was negatively associated with PD risk (OR = 0.69; 95% CI = 0.47, 1.00). Risk estimates were close to one for specific service occupations. Adjusted odds ratios for all non-service occupational and industrial categories were similar, and working in a service occupation was the only significant inverse predictor of PD risk. CONCLUSIONS: Future investigations focusing on lifestyle factors and environmental exposures within the agricultural and service occupational categories are warranted.

Passive cigarette smoke exposure of infants: importance of nonparental sources.

OBJECTIVE: To learn whether cigarette smoking by persons other than parents significantly contributes to the passive environmental tobacco smoke (ETS) exposure of infants. STUDY DESIGN: A cohort of infants prospectively followed up from birth to age 2 years with monthly questionnaires concerning smoking by different categories of adults coming into contact with the infants. SETTING: Health maintenance organization members residing in several suburban communities of Detroit, Mich, defined by contiguous ZIP codes. SUBJECTS: Ninety-seven (83%) of 117 healthy, full-term infants, thought to be at high risk of allergic disease based on cord blood IgE, who were born to eligible mothers and who completed 24 months of follow-up. MAIN OUTCOME MEASURES: Average of bimonthly urinary cotinine-creatinine ratios (CCRs) during the 2 years of the study. RESULTS: There were significant correlations (r

A second look at comorbidity in victims of trauma: the posttraumatic stress disorder-major depression connection.

BACKGROUND: We examine whether traumatic events increase the risk for major depression independent of their effects on posttraumatic stress disorder (PTSD). METHODS: Data come from the Epidemiologic Study of Young Adults in southeast Michigan (N = 1007). Retrospective and prospective data were used to estimate the risk of major depression in persons with PTSD and persons exposed to trauma with no PTSD, compared with persons who did not experience a trauma. National Comorbidity Survey data were used to evaluate the influence of trauma type. RESULTS: In the retrospective lifetime data, hazard ratios were, for first-onset major depression in exposed persons with PTSD, 2.8 and, in exposed persons with no PTSD, 1.3 (not significant), as compared with persons who were not exposed. Corresponding estimates from the prospective data were 11.7 and 1.4 (not significant). The difference in the risk for depression associated with PTSD versus exposure without PTSD is unlikely to be due to differences in trauma type. CONCLUSIONS: The findings of a markedly increased risk for major depression in persons with PTSD, but not in exposed persons without PTSD, do not support the hypothesis that PTSD and major depression in trauma victims are influenced by separate vulnerabilities.

Racial differences in physiologic parameters related to asthma among middle-class children.

BACKGROUND: Asthma morbidity and mortality are higher in the United States for African-American (AA) children when compared to European-American (EA) children. STUDY OBJECTIVES: To explore racial differences in physiologic factors associated with pediatric asthma severity. DESIGN: Cross-sectional. METHODS: We analyzed data from two groups of children in suburban Detroit, one of which contains non-urban, middle-class AA children, a group not usually included in childhood asthma studies. All children were 6 to 8 years of age. Clinical evaluations included medical history, physical examination, skin testing, spirometry, and methacholine challenge. RESULTS: The study population (n = 569) was 14% African American, 51% of the participants were male, and the mean age was 6.8 +/- 0.4 years. Socioeconomic status (parental education) was similar overall by race, although some strata-specific differences were observed. The prevalence of physician-diagnosed asthma was 10% for both AA and EA groups. AA children were more reactive to methacholine than EA children (42% vs 22%, respectively; p = 0.001), and had significantly higher total IgE than EA children (geometric mean, 60. 6 vs 27.5 IU/mL; p = 0.001). Serum IgE was related to methacholine reactivity in EA children (p = 0.001), but not AA children (p = 0. 73). These differences remained after adjustment for gender, age, parental education, parental smoking, and maternal smoking during pregnancy. CONCLUSIONS: Our data support previous reports of racial differences in lung volume, airway responsiveness, and serum IgE concentrations. We found a racial difference in the relationship between total serum IgE and airway responsiveness that is unreported elsewhere. Overall, our results suggest that AA children may be predisposed to asthma.

Factors related to methacholine airway responsiveness in children.

Studies of airway responsiveness (AR) have typically used similar dose schedules of methacholine for adults and children despite large ranges in subject size. Reported declines in AR with increasing age in children could be due to maturational changes or to proportionately smaller doses of methacholine in taller (older) children. Other investigators have related both height and various measures of lung function to AR. We examined data related to AR in 471 children, aged 6 to 8 yr, from a birth cohort. Each child underwent spirometry followed by sequential challenge with five doses of methacholine, ranging from 0.025 to 25 mg/ml, given with a dosimeter. Continuous slope and end FEV(1)-change indexes of responsiveness were computed. Using stepwise regression modeling, we found no significant association between AR and either height or age after entering a variable reflecting asthma or wheezing. In contrast, we found that baseline measures of FVC, FEV(1)/FVC, and FEF(25-75%) were significantly related to AR after controlling for other variables (p = 0.001). However, when all three of the latter measures were added to models, FEF(25-75%) was most closely related to AR. We conclude that after control for other variables, FEF(25-75%) and FVC, but not height, are significantly related to methacholine responsiveness in children.

Occupational metal exposures and the risk of Parkinson's disease.

Occupational exposure to specific metals (manganese, copper, lead, iron, mercury, zinc, aluminum and others) appears to be a risk factor for Parkinson's disease (PD) in some, but not all, case-control studies. These epidemiological studies are reviewed. Several methodological issues that may account for the lack of unanimity of findings are discussed, and suggestions for improved case-control methodology are offered. The study of the neurological disease outcome of workers who have had long-term, well-defined occupational exposure to one or more metals is also urged, with collaborative work including industrial hygienists, occupational toxicologists, neurologists, epidemiologists and biostatisticians. Such efforts, employing state-of-the-art case and control ascertainment and enrollment from suitable population bases, neurological diagnostic rigor and exposure assessment, will help to further define the potentially important roles played by metals in PD and other neurodegenerative disorders.

Vulnerability to assaultive violence: further specification of the sex difference in post-traumatic stress disorder.

BACKGROUND: We examine potential sources of the sex differences in post-traumatic stress disorder (PTSD) in the community. METHODS: Data were obtained from a representative sample of 2181 persons aged 18-45 years in the Detroit primary metropolitan statistical area, which is a six-county area containing more than four million residents. A random digit dialling method was used to select the sample and a computer-assisted telephone interview was used to obtain the data. DSM-IV PTSD was assessed with respect to a randomly selected trauma from the list of qualifying traumas reported by each respondent. RESULTS: The lifetime prevalence of exposure and the mean number of traumas were lower in females than males. The overall conditional risk of PTSD (i.e. the probability of PTSD among those exposed to a trauma) was approximately twofold higher in females than males, adjusting for the sex difference in the distribution of trauma types. The sex difference was due primarily to females' greater risk following assaultive violence. The sex difference in the avoidance and numbing symptom group following assaultive violence exceeded the sex differences in other symptom groups. CONCLUSIONS: Future research should focus on sex differences in the response to assaultive violence, including potential explanations for females' greater probability to experience avoidance and numbing.

A family history of Parkinson's disease and its effect on other PD risk factors.

Parkinson's disease (PD) is likely a result of both inherited and exogenous factors. In a study of 144 PD cases and 464 controls, we used PD family history as a surrogate for inherited PD susceptibility. Cases were more likely to report a first- or second-degree relative with PD: 16.0 vs. 4.3%; odds ratio (OR) = 4. 2; 95% confidence interval (CI) = 2.3-7.6. A PD family history was a greater risk factor for PD in subjects under age 70 (OR = 8.8; 95% CI = 3.4-22.8) compared with those over 70 (OR = 2.8; 95% CI = 1.3-6. 1) and in men (OR = 8.1; 95% CI = 3.4-19.2) compared with women (OR = 2.6; 95% CI = 1.1-6.0). We also tested whether a PD family history modified the effects of other PD risk factors. In subjects with a PD family history, occupational exposure to copper, lead or iron increased the risk for PD (OR = 3.0; 95% CI = 0.7-13.3), but this was not the case for those without a family history (OR = 1.1; 95% CI = 0.7-1.6). Ever smoking cigarettes was inversely associated with PD in those without a PD family history (OR = 0.6; 95% CI = 0.4-0.9), but was positively associated with PD in those with a PD family history (OR = 1.7; 95% CI = 0.5-5.9). In summary, our results suggest that a PD family history, and perhaps, therefore, an inherited susceptibility, confers a greater risk for PD in men and individuals under 70 years of age and may modify the effects of environmental risk factors for PD.

Evaluation of air and dust sampling schemes for Fel d 1, Der f 1, and Der p 1 allergens in homes in the Detroit area.

BACKGROUND: Studies often use a point estimate of allergen exposure without fully justifying the accuracy of this single measure as an estimate of total exposure. Many studies have reported relationships between indoor allergen concentrations and manifestations of allergic disease on the basis of single samples. OBJECTIVES: The purposes of this study were to (1) characterize the variability in dust and air concentrations of allergens, (2) assess the relationships between dust and air concentrations of allergens, and (3) determine the minimum number and timing of samples to characterize annual indoor allergen exposure. METHODS: As part of a prospective cohort study of asthma in children, air and dust samples were repeatedly obtained from the homes of children residing in suburban Detroit, Michigan. Concentrations of Fel d 1, Der f 1, and Der p 1 were measured in the samples. The results of various patterns of sampling were compared with yearly averages. RESULTS: The concentrations of all 3 allergens in both air and dust varied widely both within and between homes. The allergen concentrations had peak concentrations in the fall. There was little correlation between air and dust concentrations. Our results indicate that as few as 2 or 3 samples taken late in the year provide good estimates of the annual average concentrations. CONCLUSIONS: Two or 3 samples, obtained 1 month apart and taken late in the year, represent the best balance between sampling effort and accuracy of the yearly exposure estimates of Fel d 1, Der f 1, and Der p 1 in temperate climates similar to those of Detroit, Michigan.

Occupational exposure to manganese, copper, lead, iron, mercury and zinc and the risk of Parkinson's disease.

A population-based case-control study was conducted in the Henry Ford Health System (HFHS) in metropolitan Detroit to assess occupational exposures to manganese, copper, lead, iron, mercury and zinc as risk factors for Parkinson's disease (PD). Non-demented men and women 50 years of age who were receiving primary medical care at HFHS were recruited, and concurrently enrolled cases (n = 144) and controls (n = 464) were frequency-matched for sex, race and age (+/- 5 years). A risk factor questionnaire, administered by trained interviewers, inquired about every job held by each subject for 6 months from age 18 onward, including a detailed assessment of actual job tasks, tools and environment. An experienced industrial hygienist, blinded to subjects' case-control status, used these data to rate every job as exposed or not exposed to one or more of the metals of interest. Adjusting for sex, race, age and smoking status, 20 years of occupational exposure to any metal was not associated with PD. However, more than 20 years exposure to manganese (Odds Ratio [OR] = 10.61, 95% Confidence Interval [CI] = 1.06, 105.83) or copper (OR = 2.49, 95% CI = 1.06,5.89) was associated with PD. Occupational exposure for > 20 years to combinations of lead-copper (OR = 5.24, 95% CI = 1.59, 17.21), lead-iron (OR = 2.83, 95% CI = 1.07,7.50), and iron-copper (OR = 3.69, 95% CI = 1.40,9.71) was also associated with the disease. No association of occupational exposure to iron, mercury or zinc with PD was found. A lack of statistical power precluded analyses of metal combinations for those with a low prevalence of exposure (i.e., manganese, mercury and zinc). Our findings suggest that chronic occupational exposure to manganese or copper, individually, or to dual combinations of lead, iron and copper, is associated with PD.

Short screening scale for DSM-IV posttraumatic stress disorder.

OBJECTIVE: The authors' goal was to construct a short screening scale for DSM-IV posttraumatic stress disorder (PTSD). METHOD: They used data from the Detroit Area Survey of Trauma, which is a representative population sample of 2,181 subjects 18-45 years of age. Random digit dialing was used to select the sample, and a computer-assisted telephone interview was used to collect data on traumatic experiences and PTSD. Presence or absence of PTSD was assessed with a telephone-administered structured interview that closely followed the National Institute of Mental Health Diagnostic Interview Schedule for DSM-IV and the World Health Organization Composite International Diagnostic Interview, version 2.1. Best-subset regression analysis and receiver operating characteristic analysis were used to select a subset of items from the structured interview that most efficiently predicted PTSD as diagnosed in the full-length interview. RESULTS: A seven-symptom screening scale for PTSD was selected; five of the symptoms were from the avoidance and numbing group, and two were from the hyperarousal group. A score of 4 or greater on this scale defined positive cases of PTSD with a sensitivity of 80%, specificity of 97%, positive predictive value of 71%, and negative predictive value of 98%. CONCLUSIONS: The short screening scale is an efficient method to screen for PTSD in epidemiologic and clinical studies, given limitations on resources and burden on respondents.

Smoking and Parkinson's disease: a dose-response relationship.

OBJECTIVE: To determine whether an inverse dose-response relationship exists between cigarette smoking and PD among ever-smokers and ex-smokers. METHODS: Smoking and alcohol consumption were analyzed in 144 PD patients and 464 control subjects, who were frequency matched for sex, race, and age (+/-5 years), in a population-based case-control study of men and women > or =50 years old in the Henry Ford Health System. RESULTS: With never-smokers as the reference category, there was an inverse association between current light smokers (>0 to 30 pack-years) and PD patients (odds ratio [OR], 0.59; 95% CI, 0.23 to 1.53), and a stronger inverse association of PD with current heavy smokers (>30 pack-years; OR, 0.08; 95% CI, 0.01 to 0.62). When former >30-pack-year smokers were stratified by the interval since quitting, there was an inverse association between those who stopped >20 years ago and PD (OR, 0.86; 95% CI, 0.42 to 1.75), and a greater inverse relationship with those who stopped 1 to 20 years ago (OR, 0.37; 95% CI, 0.19 to 0.72). Alcohol consumption had no independent, significant association with PD, but heavy drinking (>10 drink-years) had a greater effect than light-moderate drinking in reducing but not eliminating the inverse association between smoking and PD. CONCLUSIONS: The inverse dose-response relationship between PD and smoking and its cessation is unlikely to be due to bias or confounding, as discussed, providing indirect evidence that smoking is biologically protective.

Adult nutrient intake as a risk factor for Parkinson's disease.

BACKGROUND: This population-based case-control study evaluated nutrient intake as a risk factor for Parkinson's disease (PD) among people aged > or =50 years in metropolitan Detroit. METHODS: Cases (n = 126) were diagnosed between 1991 and 1995 and neurologist-confirmed. Controls (n = 432) were frequency-matched for sex, age (+/-5 years) and race. Using a standardized food frequency questionnaire, subjects reported the foods they ate within the past year. RESULTS: Estimating the association between PD and risk of being in the highest versus the lowest intake quartile, there were elevated odds ratios for total fat (OR 1.94, 95% confidence interval [CI] : 1.05-3.58), cholesterol (OR 2.11, 95% CI: 1.14-3.90), lutein (OR 2.52, 95% CI: 1.32-4.84) and iron (OR 1.88, 95% CI: 1.05-3.38). CONCLUSIONS: These results suggest an association of PD with high intake of total fat, saturated fats, cholesterol, lutein and iron.

Gender differences in total and allergen-specific immunoglobulin E (IgE) concentrations in a population-based cohort from birth to age four years.

While serum immunoglobulin E (IgE) concentration has been shown to be related to allergic disease, there have been few studies of the natural history of IgE development in young children. This study compared total and allergen-specific serum IgE concentrations, by gender, from birth through 4 years of age using a population-based cohort of normal children followed from 1987 to 1993. Subjects were enrolled from a geographically defined area through membership in a large health maintenance organization, and they resided in the northern suburbs of Detroit, Michigan. Total IgE concentrations were measured at birth and at 2 and 4 years of age. Specific IgE concentrations to selected common inhalant allergens (dust mite (Dematophagoides farinae), cat, ragweed (Ambrosia artemisiifolia), and timothy grass (Pheleum pratense)) were measured at 2 and 4 years of age. Total IgE increased with age from birth to 4 years for boys and girls, and was higher in boys at 2 and 4 years of age. Girls demonstrated significant increases in IgE to mite and cat and decreases in IgE to ragweed and timothy from 2 to 4 years of age, whereas there was little change for boys except an increase in IgE to ragweed. Differences in IgE development between young boys and girls may partially account for the higher prevalence of asthma in boys than in girls.