Developmental determinants in non-communicable chronic diseases and ageing

Prenatal and peri-natal events play a fundamental role in health, development of diseases and ageing (Developmental Origins of Health and Disease (DOHaD)). Research on the determinants of active and healthy ageing is a priority to: (i) inform strategies for reducing societal and individual costs of an ageing population and (ii) develop effective novel prevention strategies. It is important to compare the trajectories of respiratory diseases with those of other chronic diseases.

Umbilical cord plasma 25-hydroxyvitamin D concentration and immune function at birth: the Urban Environment and Childhood Asthma study

BACKGROUND

Recent studies have reported conflicting data on the association between maternal intake of vitamin D during pregnancy and asthma.

OBJECTIVE

To assess the influence of prenatal vitamin D status on immune function at birth.

METHODS

In an inner-city birth cohort of 568 newborns, 520 of whom had at least one atopic parent, we measured the umbilical cord (UC) plasma concentration of 25-hydroxyvitamin D (25(OH)D) and the cytokine responses of UC blood mononuclear cells (UCMCs) to stimuli including phytohaemagglutinin (PHA), lipopolysaccharide (LPS), and peptidoglycan. In a subset, the UCMC expression of regulatory T cell markers and the suppressive activity of CD4(+) CD25(+) UCMCs were measured. Results The 25th, 50th, and 75th percentiles of UC plasma 25(OH)D level were 15.0, 20.2, and 25.6 ng/mL, respectively. Most cytokine responses of UCMC were not correlated with UC 25(OH)D concentration; however, IFN-γ release after LPS stimulation was weakly positively correlated with UC 25(OH)D concentration (r=0.11, P=0.01). PHA responses were not significantly correlated with 25(OH)D concentration. The UC plasma 25(OH)D concentration was inversely related to the number of CD25(+) (r=-0.20, P=0.06), CD25(Bright) (r=-0.21, P=0.05), and CD25(+) FoxP3 (r=-0.29, P=0.06) cells as a proportion of CD4(+) T cells in UC blood (r=-0.26, P=0.04) but not to the suppressive activity of CD4(+) CD25(+) cells (r=0.17, P=0.22).

CONCLUSION AND CLINICAL RELEVANCE

UC 25(OH)D concentration was not correlated with most UCMC cytokine responses to multiple stimuli. There was a suggestion of a weakly positive correlation with IFN-γ release after LPS stimulation. The proportions of CD25(+) , CD25(Bright) , and CD25(+) FoxP3 cells to total CD4(+) T cells were inversely correlated with UC 25(OH)D concentration. Our findings suggest that higher vitamin D levels at birth may be associated with a lower number of T-regulatory cells. Vitamin D status in utero may influence immune regulation in early life.

An English and Spanish Pediatric Asthma Symptom Scale

BACKGROUND

Pediatric asthma survey measures have not been adequately tested in non-English-speaking populations.

OBJECTIVES

To test the reliability and validity of an English and Spanish symptom scale to measure asthma control in children.

SUBJECTS

Parents (54% Spanish-speaking; 61% not high school graduates) of 234 children seen in the emergency department for an asthma exacerbation.

MEASURES

Parent report of frequency and perceived severity of child asthma symptoms during the beginning and after resolution of the exacerbation.

RESULTS

An 8-item scale composed of reports of cough, wheezing, shortness of breath, asthma attacks, chest pain, night symptoms, and overall perceived severity had very good psychometric properties in both English and Spanish. The reliability (Cronbach's alpha) of the scale ranged from 0.81 to 0.87 for both languages and time frames. In both languages, the validity of the scale was supported by responsiveness to changes in clinical status (lower symptom score after resolution of the exacerbation, P < 0.001) and by moderate to strong correlations (P < 0.001) with other asthma morbidity measures (parent report of child bother: r = 0.59-0.65; school days lost: r = 0.38-0.67; and activity days lost: r = 0.41-0.59). There were no statistically significant differences in the reliability or construct validity of the summary symptom scale by language, although Spanish speakers reported a lower frequency of some symptoms than did English speakers.

CONCLUSIONS

A reliable and valid 8-item scale can be used to measure control of asthma symptoms in Spanish-speaking populations of low literacy. Additional research to evaluate language equivalency of asthma measures is necessary.

Structure and evolution of a pair-rule interaction element: runt regulatory sequences in D. melanogaster and D. virilis

Pair-rule genes serve two important functions during Drosophila development: they first initiate periodic patterns, and subsequently interact with each other to refine these patterns to the precision required for definition of segmental compartments. Previously, we described a pair-rule input region of the runt gene. Here we further characterize this region through the use of reporter gene constructs and by comparison with corresponding sequences from Drosophila virilis. We find that many but not all regulatory properties of this '7-stripe region' are functionally conserved. Moreover, the similarity between these homologous sequences is surprisingly low. When compared to similar data for gap gene input element, our data suggest that pair-rule target sequences are less constrained during evolution, and that functional elements mediating pair-rule interactions can be dispersed over many kilobases.

Successful techniques for retention of study participants in an inner-city population

The purpose of this work was to describe methods of retaining participants in studies of inner-city populations, including the timing and intensity of contacts; and to describe the characteristics of participants who did not complete all follow-up interviews and/or return all peak flow diaries in the National Cooperative Inner-City Asthma Study. A cohort study design was used involving hospital emergency rooms and community clinics in seven major urban areas. Participants included 1337 4- to 9-year-old asthmatic children and their caretakers. Nearly 89% of participants completed 3-, 6-, and 9-month follow-up interviews. The 15% of participants who completed a baseline interview on the weekends were significantly more likely to complete follow-up interviews on a weekend. The percent of follow-up interviews conducted in person increased over time from 5% to 8%. The percent of participants with complete follow-up increased as the number of contact names increased (86% with zero contacts, 91% with two contracts; p = 0.03, test for trend). Participants who required at least four phone calls to complete the 3- and 6-month assessment were significantly more likely to be black, have higher participant stress, and have a smoker in the household (p < 0.05). Multiple logistic regression suggests that higher social support and lower parental stress were both predictors of completed interviews. Within our study sample of inner-city minority participants with asthmatic children, only a small proportion of participants missed any follow-up interviews. Increased caretaker stress, decreased social support, and inability to provide several alternate contacts were all predictive of retention problems. Having a flexible staff, computer tracking, and face-to-face recruitment appear essential to achieving nearly complete follow-up within a population historically difficult to follow.

Relationship of indoor allergen exposure to skin test sensitivity in inner-city children with asthma

BACKGROUND

It is important to understand the relationship between environmental allergen exposure dose and the risk of atopic individuals becoming sensitized to that allergen if we are to change the risk of sensitization and morbidity from allergic disease.

OBJECTIVE

The objective of these studies was to determine whether there was a dose response between current exposure to mite, cockroach, and cat allergen in inner-city children and to determine the prevalence of sensitization to these allergens.

METHODS

A sample of 500 children was selected from the 1528 children enrolled in the National Cooperative Inner City Asthma Study. Children were selected who had a sample of home dust and valid skin test responses performed with a MultiTest skin test device. The samples of home dust were collected from the floor and furniture in the kitchen, bedroom, and television/living room and were assayed for Der p 1, Der f 1, Bla g 1, and Fel d 1 allergens.

RESULTS

Each allergen level correlated significantly between rooms in individual homes. Mite (Der p 1 and Der f 1) and cat (Fel d 1) allergen levels were frequently below the detection limit of the assay. Cockroach allergen (Bla g 1) concentrations in the child's bedroom were related to the prevalence of positive skin test responses to cockroach allergen extract among the children, with an odds ratio for sensitization of 1.45 (1.11-1.92). Positive skin test responses to cockroach allergen were seen in 15% of children exposed to bedroom dust with a Bla g 1 concentration below the level of detection compared with a rate of 32% in bedrooms with Bla g 1 levels of 1 to 2 U/g and 40% to 44% among those in rooms with 4 U/g or greater. The relationship between exposure and positive skin test responses was clearly stronger among atopic children with a greater number of positive skin test responses.

CONCLUSIONS

Despite widespread exposure to household allergens, the strongest relationship between exposure and sensitization was seen in the bedroom. The dose response between exposure to cockroach allergen and sensitization suggested that exposure to low doses of allergen, 2 U/g or less, was a risk factor and that the risk plateaus above 4 U/g. Atopy modified the relationship of exposure to sensitization.

Vitamin-mineral supplement use among preschool children in the United States

OBJECTIVE

To estimate the prevalence of recent supplement use in a national sample of preschool children and to examine the relationship of maternal and child characteristics, past maternal supplement use practices, familial, health services, and child health factors associated with supplement use.

METHODS

We used data on 8285 preschool children whose mothers were interviewed for the 1991 Longitudinal Follow-up to the 1988 National Maternal and Infant Health Survey. Data collection was conducted either by telephone or personal interview. The sample is representative of the estimated 3. 8 million US born children in 1988 and alive in 1991. The outcome measures are whether the child was given any vitamin and mineral supplements at least 3 days a week in the 30 days before the interview and the type of supplement received. Statistical techniques included bivariate and weighted multiple logistic regression analysis.

RESULTS

More than half of all US 3-year-olds (54.4%) were given some vitamin and mineral supplement. The most common supplements consumed were multivitamin-mineral with iron (59% of supplement users) and multivitamin-mineral without iron (26.4%). Children who received any supplements tended to have mothers who are non-Hispanic White, older, more educated, married, insured, receiving care from a private health care provider, have greater household income, and took supplements during pregnancy. Child health characteristics associated with supplement use included first birth order and having eating problems or poor appetites.

CONCLUSIONS

More than half of US preschool children used vitamin and mineral supplements. The sociodemographic and health predictors identified for supplement use suggest that groups at risk for nonuse are likely the same groups whose circumstances may predispose a need for supplementation.

Design and methods of the National Cooperative Inner-City Asthma Study

The National Cooperative Inner-City Asthma Study (NCICAS) was established to identify and then intervene on those factors which are related to asthma morbidity among children in the inner-city. This paper describes the design and methods of the broad-based initial Phase I epidemiologic investigation. Eight research centers enrolled 1,528 children, 4 to 9 years of age, from English- or Spanish-speaking families, all of whom resided in major metropolitan inner-city areas. The protocol included an eligibility assessment and an extensive baseline visit, during which symptom data, such as wheezing, lost sleep, changes in activities of daily living, inpatient admissions, and emergency department and clinic visits were collected. A comprehensive medical history for each child was taken and adherence to the medical regimen was assessed. Access, as well as barriers, to the medical system were addressed by a series of questions including the location, availability, and consistency of treatment for asthma attacks, follow-up care, and primary care. The psychological health of the caretaker and of the child was also measured. Asthma knowledge of the child and caretaker was determined. Sensitization to allergens was assessed by skin-prick allergen testing and exposure to cigarette smoke and the home environment were assessed by questionnaire. For more than a third of the families, in-home visits were conducted with dust sample allergen collection and documentation of the home environment, such as the presence of pets and evidence of smoking, mildew, and roaches. Urine specimens were collected to measure passive smoke exposure by cotinine assays, blood samples were drawn for banking, and children age 6 to 9 years were given spirometric lung function assessment. At 3, 6 and 9 months following the baseline assessment, telephone interviews were conducted to ask about the child's symptoms, unscheduled emergency department or clinic visits, and hospitalizations. At this time, peak flow measurements with 2-week diary symptom records were collected.

Characteristics of inner-city children with asthma: the National Cooperative Inner-City Asthma Study

Asthma morbidity has increased dramatically in the past decade, especially among poor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study (NCICAS) is a multicenter study designed to determine factors that contribute to asthma morbidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old, were enrolled in a broad-based epidemiologic investigation of factors which were thought to be related to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adherence and access to care, home visits, and pulmonary function. Interval assessments were conducted at 3, 6, and 9 months after the baseline evaluations. Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two or more. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recall periods. The pattern of skin test sensitivity differed from other populations in that positive reactions to cockroach were higher (35%) and positive reactions to house dust mite were lower (31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (> 40 ppb) to nitrogen dioxide was found in 24% of homes. Although the majority of children had insurance coverage, 53% of study participants found it difficult to get follow-up asthma care. The data demonstrate that symptoms are frequent but do not result in hospitalization in the majority of children. These data indicate a number of areas which are potential contributors to the asthma morbidity in this population, such as environmental factors, lack of access to care, and adherence to treatment. Interventions to reduce asthma morbidity are more likely to be successful if they address the many different asthma risks found in the inner cities.

The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma

BACKGROUND

It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust.

METHODS

From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period.

RESULTS

Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen.

CONCLUSIONS

The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.

Pair-rule expression of the Drosophila fushi tarazu gene: a nuclear receptor response element mediates the opposing regulatory effects of runt and hairy

The segmentation genes runt and hairy are required for the proper transcriptional regulation of the pair-rule gene fushi tarazu during the blastoderm stage of Drosophila embryogenesis. The expression of different fushi tarazu reporter genes was examined in runt and hairy mutant embryos, as well as in runt over-expressing embryos in order to identify DNA elements responsible for mediating these regulatory effects. The results indicated that runt and hairy act through a common 32 base-pair element. This element, designated as fDE1, contains a binding site for a small family of orphan nuclear receptor proteins that are uniformly expressed in blastoderm embryos. The pair-rule expression of reporter gene constructs containing multimerized fDE1 elements depends on activation by runt and repression by hairy. Examination of reporter genes with mutated fDE1 elements provided further evidence that this element mediates both transcriptional activation and repression. Genetic experiments indicated that the opposing effects of runt and hairy were not due solely to cross-regulatory interactions between these two genes and that fDE1-dependent expression is regulated by factors in addition to runt and hairy.