Does breast feeding help protect against atopic disease? Biology, methodology, and a golden jubilee of controversy

Human milk polyunsaturated long-chain fatty acids and secretory immunoglobulin A antibodies and early childhood allergy

The possible protective effect of breast milk against atopic manifestations in infancy, i.e. atopic eczema and food allergy, has been controversial for the last decades. Besides the methodological problems, differences in the composition of human milk could explain these controversies. The aim of this study was to investigate the composition of polyunsaturated fatty acids (PUFA) and secretory immunoglobulin A (S-IgA) levels to food proteins (ovalbumin and beta-lactoglobulin) and an inhalant allergen (cat) in milk from mothers of allergic and non-allergic children. Blood samples were obtained at birth and at 3 months from 120 children. Skin prick tests were performed at 6, 12 and 18 months, and the development of atopic diseases was assessed in the children. Breast milk samples were collected from their mothers at birth and monthly during the lactation period. Milk PUFA composition was measured by gas chromatography, and enzyme-linked immunosorbent assay (ELISA) was used to measure total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA. Allergic disease developed in 44/120 children (22/63 children of allergic mothers and 22/57 children of non-allergic mothers). Lower levels of eicosapentaenoic acid, C20:5 n-3 (EPA), docosapentaenoic acid C22:5 n-3 (DPA), and docosatetraenoic acid C22:4 n-6 (DHA) (p < 0.05 for all) were found in mature milk from mothers of allergic as compared to milk from mothers of non-allergic children. The total n-6:total n-3 and the arachidonic acid, C20:4 n-6 (AA):EPA ratios were significantly lower in transitional and mature milk from mothers of allergic children, as compared to milk from mothers of non-allergic children. The PUFA levels in serum of allergic and non-allergic children were largely similar, except for higher levels of C22:4 n-6 and C22:5 n-6 (p < 0.05 for both) and a higher AA:EPA ratio in serum phospholipids in the former group (p < 0.05). Changes in the levels of milk PUFA were reflected in changes in PUFA serum phospholipids, particularly for the n-6 PUFA. The AA: EPA ratio in maternal milk was related, however, to the AA:EPA only in serum from non-allergic children, while this was not the case in allergic children. The levels of total S-IgA, anti-cat S-IgA, anti-ovalbumin S-IgA, and anti-beta-lactoglobulin S-IgA in milk from mothers of allergic, as compared to non-allergic, children were similar through the first 3 months of lactation. Low levels of n-3 PUFA in human milk, and particularly a high AA:EPA ratio in maternal milk and serum phospholipids in the infants, were related to the development of symptoms of allergic disease at 18 months of age. The milk PUFA composition influenced the composition of PUFA in serum phospholipids of the children. We also showed that the lower levels of colostral anti-ovalbumin S-IgA and lower total S-IgA in mature milk from atopic mothers did not influence the development of allergic disease in the children up to 18 months of age. The findings indicate that low alpha-linolenic acid, C18:3 n-3 (LNA) and n-3 long-chain polyunsaturated fatty acids (LCP) 20-22 carbon chains, but not the levels of S-IgA antibodies to allergens, are related to the development of atopy in children.

Is maternal smoking harmful to the physical growth of offspring at early childhood?

The effect of maternal smoking on birth weight of their babies, the effects of smoking during lactation and in the post-weaning period on growth in height and weight of children up to the age of 7 years were investigated. The sample consisted of 1511 children (778 boys and 733 girls) examined at two follow-up studies in May and December 1997. Retrospective data on birth-weight, height and weight up to the present investigation were available from the child’s health record book. The results of the investigation revealed more frequent occurrence of lower birth-weight among children born to mothers smoking during pregnancy than among those born to non-smokers. Similar results were also gained for children in the pre-school period.

Risk factors for early, persistent, and late-onset wheezing in young children. SIDRIA Collaborative Group

Wheezing in childhood is not a single disorder and different wheezing-associated respiratory illnesses have been recently described. We investigated the association between wheezing conditions and familial, pre-, peri-, and postnatal risk factors. We studied 16,333 children, 6 to 7 yr old, enrolled in a population-based study. Standardized questionnaires were filled in by parents. A total of 1,221 children had transient early wheezing, 671 had persistent wheezing, 918 had late-onset wheezing, and 13,523 never had wheezing or asthma (control group). Maternal asthma or chronic obstructive airway disease were significantly (p < 0.0001) more associated with persistent wheezing than with transient early and late-onset wheezing. The same pattern was observed for exposure to maternal smoke during pregnancy. Having a mother > 35 yr old was protective against transient early wheezing (odds ratio [OR]: 0.68, 95% confidence intervals [95% CI]: 0.53 to 0.86). Breast feeding >/= 6 mo was slightly protective against transient early wheezing (OR: 0.82, 95% CI: 0.68 to 0.97), whereas it was a moderate risk factor for late-onset wheezing (OR: 1.22, 95% CI: 0.99 to 1.50). On the contrary, having siblings and attending a day care center were both risk factors for transient early wheezing (OR: 1.41 [95% CI: 1.21 to 1.64] and 1.70 [95% CI: 1.48 to 1.96], respectively) and protective factors against wheezing of late onset (OR: 0.83 [95% CI: 0.70 to 0.97] and 0.72 [95% CI: 0.59 to 0.88]). There was a stronger (p < 0.0001) positive association between personal history of eczema or allergic rhinitis and persistent and late-onset wheezing than transient early wheezing. Our findings suggest a different contribution of risk factors to wheezing conditions in childhood.

Association between breast feeding and asthma in 6 year old children: findings of a prospective birth cohort study

OBJECTIVES

To investigate the association between the duration of exclusive breast feeding and the development of asthma related outcomes in children at age 6 years.

DESIGN

Prospective cohort study.

SETTING

Western Australia.

SUBJECTS

2187 children ascertained through antenatal clinics at the major tertiary obstetric hospital in Perth and followed to age 6 years.

MAIN OUTCOME MEASURES

Unconditional logistic regression to model the association between duration of exclusive breast feeding and outcomes related to asthma or atopy at 6 years of age, allowing for several important confounders: sex, gestational age, smoking in the household, and early childcare.

RESULTS

After adjustment for confounders, the introduction of milk other than breast milk before 4 months of age was a significant risk factor for all asthma and atopy related outcomes in children aged 6 years: asthma diagnosed by a doctor (odds ratio 1.25, 95% confidence interval 1.02 to 1.52); wheeze three or more times since 1 year of age (1.41, 1.14 to 1.76); wheeze in the past year (1.31, 1.05 to 1.64); sleep disturbance due to wheeze within the past year (1.42, 1.07 to 1.89); age when doctor diagnosed asthma (hazard ratio 1.22, 1.03 to 1.43); age at first wheeze (1.36, 1.17 to 1.59); and positive skin prick test reaction to at least one common aeroallergen (1.30, 1.04 to 1.61).

CONCLUSION

A significant reduction in the risk of childhood asthma at age 6 years occurs if exclusive breast feeding is continued for at least the 4 months after birth. These findings are important for our understanding of the cause of childhood asthma and suggest that public health interventions to optimise breast feeding may help to reduce the community burden of childhood asthma and its associated traits.

Different pattern of risk factors for atopic and nonatopic asthma among children--report from the Obstructive Lung Disease in Northern Sweden Study

BACKGROUND

A cross-sectional study was performed among 78-year-old schoolchildren during the winter of 1996 in three municipalities in the most northern province of Sweden, Norrbotten. The study was the starting point of a longitudinal study of asthma, rhinitis, eczema, and type-1 allergy, and provided data on prevalence and risk factors for these conditions. The aim of the present study was to validate the classification of asthma based on a parental questionnaire, and to examine risk factors for atopic and nonatopic asthma.

METHODS

The ISAAC questionnaire with additional questions was distributed by the schools to the parents. The response rate was 97%, and 3431 completed questionnaires were returned. The children in Kiruna and Luleå were also invited to be skin tested, and 2149 (88%) were tested with 10 common airborne allergens. A structured interview was administered by pediatricians in stratified samples of the children to test the validity of the diagnosis of asthma based on the questionnaire.

RESULTS

After the validation study, the prevalence of "ever asthma" was estimated to be 8.0%. The specificity of the question, "Has your child been diagnosed as having asthma by a physician?", was high, >99%, while the sensitivity was around 70%. The strongest risk factor for "ever asthma" was a positive skin test (OR 3.9). Risk factors for asthma in the asthmatics who were not sensitized were family history of asthma, OR 3.6; breast-feeding less than 3 months, OR 1.8; past or present dampness at home, OR 1.8; smoking mother, OR 1.7; and male sex, OR 1.6. Among the sensitized asthmatics, only a family history of asthma was a significant risk factor (OR 3.0), while breast-feeding less than 3 months was not associated with an increased risk (OR 1.0). A synergistic effect between genetic and environmental factors was found especially in the nonatopic asthmatics; the children with a family history of asthma who had a smoking mother and past or present dampness at home had an OR for "ever asthma" of 13.

CONCLUSIONS

Different risk-factor patterns were found for asthma and type-1 allergy. In addition, the risk factors for atopic or allergic asthma diverged from those for nonatopic asthma.

Breast-feeding, maternal IgE, and total serum IgE in childhood

BACKGROUND

There is controversy regarding the relationship of the effect of breast-feeding on markers of allergy such as total serum IgE in childhood.

OBJECTIVE

This study, using longitudinal data, tested the hypothesis that the relation of breast-feeding to IgE in childhood differs depending on maternal total IgE level.

METHODS

Total serum IgE was assessed with the paper radioimmunosorbent test at 4 ages in nonselected children enrolled at birth into the prospective Tucson Children's Respiratory Study. Children were classified as never breast-fed, breast-fed less than 4 months, or breast-fed 4 months or longer, on the basis of physician report or questionnaires completed by parents by the time the child was 18 months old. A longitudinal random effects model was used to test for group differences and temporal trends in IgE for children classified with reference to maternal IgE (high tertile vs all others) and breast-feeding history. A total of 664 children with 1457 observations were included.

RESULTS

Among children whose mothers were in the 2 lower tertiles of IgE, breast-feeding was associated with lower total serum IgE at age 6 years (24.2 vs 44.3 IU/mL for never breast-fed children; P <.02); similar trends existed at age 11 years. In contrast, for children whose mothers were in the highest tertile of IgE, breast-feeding of 4 months or longer was associated with higher IgE levels in the child compared with those never breast-fed or breast-fed less than 4 months (97.0 vs 38.9 IU/mL; P <. 005). These cross-sectional analyses were confirmed with the longitudinal random effects model, which also showed no effect of confounders. Paternal IgE showed no similar relation with child IgE.

CONCLUSION

Breast-feeding appears to have paradoxic relations with IgE in childhood, depending on maternal IgE level. These findings may help explain the contradictory results found in other investigations of the relation of breast-feeding to allergic symptoms and markers.

PEDIATRIC ALLERGY

The current paradigm of allergy pathogenesis is that allergy develops in individuals with a genetic predisposition only after they are exposed to allergens (Fig. 1). This hypothesis implies that factors in the environment can determine the initiation of allergic sensitization and can potentially influence the clinical manifestations and severity of disease. Because the prevalence of atopic diseases such as allergic rhinitis, asthma, atopic dermatitis, and food allergy have increased worldwide in the past several decades, and there is no mechanism for changes in population genetics over this short period of time, changes in the human environment are most likely responsible for these trends. From this line of reasoning, it follows that if the factors responsible for the increasing prevalence can be identified, then there would be an opportunity to develop strategies to reverse these trends. It also would be helpful to identify infants who are at risk for developing allergy, so that preventive strategies could be used most effectively.

In this article, studies to determine the contributions of genetics and the environment to the development of allergic diseases in childhood are explored. In addition, progress in identifying risk factors for allergy and preventive therapies for those children at risk are also addressed.

Prediction of early-onset asthma in genetically at-risk children

The W.T. Grant Foundation Asthma Risk Study was designed to prospectively examine children who were considered at a genetically increased risk for the development of asthma. The respective contributions of 11 potential risk factors, both environmental and biological, were assessed in order to determine their relative roles in affecting the early onset of asthma. This is a report of an inception cohort of children born to asthmatic mothers and followed for a 3-year period. All 150 families were recruited from the general community and living within 2 h of the National Jewish Center for Immunology and Respiratory Medicine (Denver, CO). Mothers in the index risk sample had been previously diagnosed with asthma and were recruited during their pregnancy through physician referrals and media solicitation. The index sample of 150 families was 92% Caucasian and predominantly middle class. The mean age of mothers was 29.3 years, and of fathers, 31.1 years. The main outcome was the determination of the early onset of asthma and its association with quantified risk factors. By age 3 years, 14 of the 150 children had developed asthma. Frequent illness, IgE levels at age 6 months, parenting difficulties, and early eczema were significantly associated with the onset of asthma (P = 0.003, P = 0.006, P = 0.01, and P = 0.03, respectively). Only frequent illness, elevated serum IgE levels, and parenting difficulties entered a predictive model where they were independently related to the development of asthma.

Infant feeding styles of West Indian women

An ethnographic field study design was used to explore infant feeding among 20 West Indian women on the island of St. Croix, United States Virgin Islands. Two styles of infant feeding emerged from the data, "older style" and "contemporary style." Three patterns of combined breast and bottle feeding were identified: day/night, supplemental, and random. Older style mothers followed a day/night pattern, whereas contemporary style mothers used a supplemental pattern. A folk explanatory model of infant feeding was constructed and included why infants were fed in certain ways, as well as the meaning of feeding practices. The health care system had an impact on both styles of infant feeding through hospital practices and provision of formula through the Women, Infants, and Children (WIC) program.

Breast-feeding of allergic infants

OBJECTIVE

Infants may have allergic disease even during exclusive breast-feeding. The aim of this study was to evaluate whether allergic infants should continue breast-feeding.

STUDY DESIGN

We studied 100 infants who had atopic eczema during exclusive breast-feeding. The extent and severity of the eczema, allergic sensitization, and the patients' growth and nutrition were assessed during and after cessation of breast-feeding.

RESULTS

The mean body length SD score decreased at the onset of allergic disease, and an association was seen between the duration of symptoms and poor growth (r = -.23, P =.04). Some improvement could be achieved by strict elimination diet by the mothers. The atopic eczema improved significantly after breast-feeding was stopped: SCORAD score 20 (range 15 to 27) during and 7 (range 4 to 11) after breast-feeding; t = 5.38, P <.0001, and the relative length of patients increased, in parallel with improved nutritional parameters.

CONCLUSIONS

Breast-feeding should be promoted for primary prevention of allergy, but breast-fed infants with allergy should be treated by allergen avoidance, and in some cases breast-feeding should also be stopped. This particularly applies to infants with atopic eczema who also have impaired growth.

Breastfeeding provides passive and likely long-lasting active immunity

OBJECTIVES

The reader of this review will learn about the mechanisms through which breastfeeding protects against infections during and most likely after lactation, as well as possibly against certain immunologic diseases, including allergy.

DATA SOURCES

I have followed the literature in the area closely for the last 30 to 40 years and have made repeated literature searches through MEDLINE, most recently in 1998. Textbooks and peer-reviewed journals have been sought for, as well as books representing meeting reports in English, French, German, and Spanish.

RESULTS

Human milk protects against infections in the breastfed offspring mainly via the secretory IgA antibodies, but also most likely via several other factors like the bactericidal lactoferrin. It is striking that the defense factors of human milk function without causing inflammation, some components are even directly anti-inflammatory. Protection against infections has been well evidenced during lactation against, e.g., acute and prolonged diarrhea, respiratory tract infections, otitis media, urinary tract infection, neonatal septicemia, and necrotizing enterocolitis. There is also interesting evidence for an enhanced protection remaining for years after lactation against diarrhea, respiratory tract infections, otitis media, Haemophilus influenzae type b infections, and wheezing illness. In several instances the protection seems to improve with the duration of breastfeeding. Some, but not all studies have shown better vaccine responses among breastfed than non-breastfed infants. A few factors in milk like anti-antibodies (anti-idiotypic antibodies) and T and B lymphocytes have in some experimental models been able to transfer priming of the breastfed offspring. This together with transfer of numerous cytokines and growth factors via milk may add to an active stimulation of the infant's immune system. Consequently, the infant might respond better to both infections and vaccines. Such an enhanced function could also explain why breastfeeding may protect against immunologic diseases like coeliac disease and possibly allergy. Suggestions of protection against autoimmune diseases and tumors have also been published, but need confirmation.

CONCLUSIONS

Breastfeeding may, in addition to the well-known passive protection against infections during lactation, have a unique capacity to stimulate the immune system of the offspring possibly with several long-term positive effects.

Randomised controlled trial of brief neonatal exposure to cows' milk on the development of atopy

OBJECTIVE

To determine the effect of brief early exposure to cows' milk on atopy in the first 2 years of life.

DESIGN

Double blind, placebo controlled, randomised feeding intervention trial (Bokaal study).

SETTING

Dutch midwifery practices.

PARTICIPANTS

1533 breast fed neonates.

INTERVENTION

Exposure to cows' milk protein (n = 758) or a protein free placebo (n = 775) during the first 3 days of life.

MAIN OUTCOME MEASURES

Clinical atopic disease and any positive radioallergosorbent (RAST) tests at 1 year of age.

RESULTS

Atopic disease in the first year was found in 10.0% (cows' milk) v 9.3% (placebo) of the children, with a relative risk of 1.07; in the second year, atopic disease was found in 9.6% v 10.2%, respectively, with a relative risk of 0.94. Per protocol analysis showed similar results. Any RAST positive test was found in 9.4% (cows' milk) v 7.9% (placebo) of children, with a relative risk of 1.19. Stratified analysis for high family risk of allergy showed a doubled incidence of atopic disease but no effect from the intervention.

CONCLUSION

Early and brief exposure to cows' milk in breast fed children does not increase the risk of atopic disease in the first 2 years.

Does breast-feeding influence intelligence quotients at 9 and 10 years of age?

The effect of breast-feeding on intellectual development remains controversial. We explored this relationship in a high socioeconomic population in which breast-feeding was supplemented with soy containing formulas at some time during the first year of life. As part of the 1988 National Institute of Child Health and Human Development school-based survey of two metropolitan Washington, D.C. counties to identify children in the 1978 to 1979 birth cohort who had been exposed to the chloride deficient formulas Neo-Mull-Soy and Cho-Free during infancy, information on breast-feeding was also obtained on children exposed to the chloride-deficient formulas and a group of control children exposed to other soy formulas. Because no differences in intellectual development were observed between the two groups, they were combined and the effect of breast-feeding on intellectual development at 9 and 10 years was assessed. There were 176 infants that received no breast-feeding and 342 who were breast-fed. The median duration of breast-feeding was 124 days (interquartile range, 42-248 days). There were no differences in birth weight, gender or race between the infants who were breast-fed and those who were not. The mean Weschler Intelligence Scale-Revised Full Scale IQ was 122 among those breast-fed compared to 118 among those that were not (P = 0.0008). However, following adjustment by linear regression for maternal education, paternal education and annual income the adjusted mean full scale IQ was 111 among the breast-fed and 110 among the non-breast-fed (P = 0.23). Further analyses limited to those exclusively breast-fed for the first 60 days failed to demonstrate any significant relationship between breast-feeding and IQ.

The allergy march: from food to pollen

There is epidemiological evidence, especially from longitudinal studies, that clinical manifestations of atopy as well as IgE antibodies against food and aeroallergens show a systematic sequence of events. The atopic march begins with food allergy associated gastrointestinal disorders and atopic dermatitis followed by respiratory allergies, i.e. asthma and atopic rhino-conjunctivitis. Detectable food antibodies, especially against egg and milk proteins, usually precede or accompany the early clinical symptoms and signs. Similarly, aeroallergen sensitization, first against indoor allergen antibodies, succeeded by outdoor allergen antibodies, precede the clinical manifestation of respiratory allergy. Early atopic events, either manifestation or sensitization can be used as risk markers or even predictors of atopic disorders to implement preventive measures. Early atopic dermatitis as well as elevated serum IgE antibodies against food allergens in the first two years of life in combination with a family history can be used as a predictor for aeroallergen sensitization.

Eczema, asthma and allergy

The literature in relation to the development of atopic and allergic disorders has been reviewed, in order to assess the claim that prolonged and exclusive breast feeding protects against the development of such disorders. The data in the literature show little consistent evidence to identify any protective association between breast feeding and either eczema, wheezing/asthma or other types of atopy or allergic response.

Is breastfeeding beneficial and maternal smoking harmful to the cognitive development of children?

The effects of breastfeeding on cognitive, visuomotor and language development were examined in healthy children born at full term, after they had reached 56 months of age. Three hundred and sixty-three children were breastfed for less than 5 months, and 363 for 5 months or more. The groups were matched pairwise having regard to maternal education and sex of the child. Significant differences were found in relation to scores reflecting general cognitive capacity, and the results of the visuomotor integration test between children breastfed for less than 5 months and those breastfed for 5 months or more, and between children of mothers who had smoked during pregnancy and non-smoking mothers. In multiple linear regression analysis prolonged breastfeeding was significantly related to scores reflecting general cognitive capacity and results of the visuomotor integration test. However, smoking by mothers during pregnancy was not significantly related to scores in cognitive tests. Biological factors, and factors such as lifestyle and social background, may be more important determinants of a child's development than breastfeeding.

Measles and atopy in Guinea-Bissau

BACKGROUND

Epidemiological studies have led to speculation that infections in early childhood may prevent allergic sensitisation but evidence to support this hypothesis is lacking. We investigated whether measles infection protects against the development of atopy in children of Guinea-Bissau, West Africa.

METHODS

We conducted a historical cohort study in Bandim, a semi-rural district of Bissau, the capital of Guinea-Bissau. 395 young adults, first surveyed in 1978-80 aged 0-6 years, were followed up in 1994. Our analyses were restricted to 262 individuals still living in Bandim for whom a measles history, documented in childhood, was judged to be reliable. We defined atopy as skin-prick test positivity (> or = 3 mm weal) to one or more of seven allergens.

FINDINGS

17 (12.8 percent) of 133 participants who had had measles infection were atopic compared with 33 (25.6 percent) of 129 of those who had been vaccinated and not had measles (odds ratio, adjusted for potential confounding variables 0.36 [95 percent CI 0.17-0.78], p=O.O1). Participants who had been breastfed for more than a year were less likely to have a positive skin test to housedust mite. After adjustment for breastfeeding and other variables, measles infection was associated with a large reduction in the risk of skin-prick test positivity to housedust mite (odds ratio for Dermatophagoides pteronyssinus 0.20 [0.05-0.81], p=0.02; D farinae 0.20 [0.06-0.71], p=0.01).

INTERPRETATION

Measles infection may prevent the development of atopy in African children.

Incidence and prognosis of asthma and wheezing illness from early childhood to age 33 in a national British cohort

OBJECTIVE

To describe the incidence and prognosis of wheezing illness from birth to age 33 and the relation of incidence to perinatal, medical, social, environmental, and lifestyle factors.

DESIGN

Prospective longitudinal study.

SETTING

England, Scotland and Wales.

SUBJECTS

18,559 people born on 3-9 March 1958. 5801 (31%) contributed information at ages 7, 11, 16, 23, and 33 years. Attrition bias was evaluated using information on 14, 571 (79%) subjects.

MAIN OUTCOME MEASURE

History of asthma, wheezy bronchitis, or wheezing obtained from interview with subjects' parents at ages 7, 11, and 16 and reported at interview by subjects at ages 23 and 33.

RESULTS

The cumulative incidence of wheezing illness was 18% by age 7, 24% by age 16, and 43% by age 33. Incidence during childhood was strongly and independently associated with pneumonia, hay fever, and eczema. There were weaker independent associations with male sex, third trimester antepartum haemorrhage, whooping cough, recurrent abdominal pain, and migraine. Incidence from age 17 to 33 was associated strongly with active cigarette smoking and a history of hay fever. There were weaker independent associations with female sex, maternal albuminuria during pregnancy, and histories of eczema and migraine. Maternal smoking during pregnancy was weakly and inconsistently related to childhood wheezing but was a stronger and significant independent predictor of incidence after age 16. Among 880 subjects who developed asthma or wheezy bronchitis from birth to age 7, 50% had attacks in the previous year at age 7; 18% at 11, 10% at 16, 10% at 23, and 27% at 33. Relapse at 33 after prolonged remission of childhood wheezing was more common among current smokers and atopic subjects.

CONCLUSION

Atopy and active cigarette smoking are major influences on the incidence and recurrence of wheezing during adulthood.

Human milk proteins may interfere in ELISA measurements of bovine beta-lactoglobulin in human milk

It is widely believed that cow's milk proteins ingested by the mother, in particular beta-lactoglobulin (beta-LG), can pass into breast milk and thus sensitize predisposed infants. However, studies to evaluate bovine beta-LG in human milk have given conflicting results. The aim of this study was to analyse the correlation between the amount of cow's milk in the mother's diet and the presence of bovine beta-LG in breast milk. Human milk samples from 14 healthy non-atopic women on diets with different cow's milk contents were examined. The total concentration of bovine beta-LG or beta-LG immuno-like proteins (beta-LGIP) was determined by enzyme-linked immunosorbent assay (ELISA). Two separation procedures utilizing ELISA plates and an affinity chromatography column were set up to identify the human whey components recognized by the anti-beta-LG antibodies. beta-LGIP reactivities of milk from three groups on different diets were not significantly different. After splitting the antigen-antibody complexes, three main protein components, human lactoferrin, human beta-casein and human alpha-lactalbumin, were identified. This study would suggest that, at least in healthy subjects, false-positive results in ELISA determinations of bovine beta-LG in human milk might be due to cross-reactions between polyclonal antibodies and different protein antigens.

Atopic dermatitis: is it an allergic disease?

For many years controversy has surrounded the relation between allergy and atopic dermatitis. We critically review the evidence for the contribution of allergy, or IgE-mediated hypersensitivity reactions, to the pathogenesis of this disease. We conclude that, at present, there is scant evidence that allergy is central to the development of atopic dermatitis, although it may be an aggravating factor in a few patients. Hence there is little rationale for the routine use of allergy testing or dietary and environmental manipulation in the management of this disease.

Parental smoking and other risk factors for wheezing bronchitis in children

A population-based case-control study was performed to investigate etiologic factors for wheezing bronchitis and asthma in children up to four years of age. A total of 199 children hospitalized for the first time with these diagnoses at a major hospital in Stockholm in 1986-1988 constituted the cases, 351 children from the catchment area of the hospital were used as controls. Information on known and suspected risk factors was obtained through home interviews with a parent. Parental smoking was associated with a relative risk of 1.8 (95% confidence interval 1.3-2.6) corresponding to a population attributable proportion of 27%. The strongest association was seen for maternal smoking and children below 18 months of age. Other major risk factors included atopic heredity, recurrent upper respiratory tract infections and breast-feeding less than 3 months, which appeared to interact multiplicatively with parental smoking. The environmental factors had a stronger influence in the youngest age group, and the overall attributable proportion associated with parental smoking, short breast-feeding period and exposure to pets in the household was 43%. It is clear that successful primary prevention could dramatically reduce the incidence of wheezing bronchitis in children.

Breast-feeding protects against otitis media

Although exclusive breast-feeding decreases infant mortality and morbidity in developing countries, its protective effects in infants living in industrialized nations have been more difficult to quantitate. A recent study provides strong evidence that exclusive breast-feeding for at least four months decreases the incidence of otitis media in the first year of life.

Relation between early introduction of solid food to infants and their weight and illnesses during the first two years of life

OBJECTIVE

To assess the relations between early introduction of solid food and infant weight, gastrointestinal illness, and allergic illnesses during the first two years of life.

DESIGN

Prospective observational study of infants followed up for 24 months after birth.

SETTING

Community setting in Dundee.

PATIENTS

671 newborn infants, of whom 455 were still available for study at 2 years of age.

MAIN OUTCOME MEASURES

Infants' diet, weight, and incidence of gastrointestinal illness, respiratory illness, napkin dermatitis, and eczema at 2 weeks and 2, 3, 4, 6, 9, 12, 15, 18, 21, and 24 months of age.

RESULTS

The infants given solid food at an early age (at < 8 weeks or 8-12 weeks) were heavier than those introduced to solids later (after 12 weeks) at 4, 8, 13, and 26 weeks of age (p < 0.01) but not at 52 and 104 weeks. At their first solid feed those given solids early were heavier than infants of similar age who had not yet received solids. The incidence of gastrointestinal illness, wheeze, and nappy dermatitis was not related to early introduction of solids. There was a significant but less than twofold increase in respiratory illness at 14-26 weeks of age and persistent cough at 14-26 and 27-39 weeks of age among the infants given solids early. The incidence of eczema was increased in the infants who received solids at 8-12 weeks of age.

CONCLUSION

Early introduction of solid food to infants is less harmful than was previously reported. Longer follow up is needed, but, meanwhile, a more relaxed approach to early feeding with solids should be considered.

Early feeding of preterm infants and allergic symptoms during childhood

A follow-up study of 69 premature infants showed that at a mean age of 11.4 years they had a cumulative incidence of allergic symptoms similar to that reported in unselected series. The 38 premature infants fed exclusively with human milk to the age of four months had more allergic symptoms than the 31 premature infants fed with adapted cow's milk formula from birth (mean number of symptoms 1.6 versus 0.6, p = 0.0025). The excess of symptoms was mostly cutaneous, and often associated with a specific food. In logistic regression models, the only variable with a statistically significant association (standardized odds ratio 3.15, 95% confidence interval 1.12-8.8, p = 0.03) with symptomatic allergy was the type of feed. The frequency of positive skin prick tests and the mean levels of serum IgE and antibodies to cow's milk were similar in the two groups. We infer that food allergy was more common in the group fed with human milk.

Cow's milk, diabetes, and infant feeding

Recently, a link between the serum level of antibody to cow's milk protein and the onset of insulin-dependent diabetes mellitus in humans was reported. This observation renewed controversy regarding the suitability of cow's milk in infant diets.

Higher risk of infantile atopic dermatitis from maternal atopy than from paternal atopy

The risk of infantile atopic dermatitis (AD) posed by maternal atopy and paternal atopy, respectively, were compared in the infants from a birth cohort in whom one of the parents had been designated atopic by skin prick testing. Nineteen with atopic mothers were compared with 20 with atopic fathers. AD, other atopic manifestations and potentially influential factors such as breast-feeding were documented prospectively during the first year in all infants. At 3, 6 and 12 month assessments skin prick sensitivity and total serum IgE concentration were determined. Nine of 19 infants with atopic mothers and two of 20 with atopic fathers had AD (P = 0.023) giving a relative risk of 4.7 (95% confidence interval 2.5 to 9.0). Seven of 19 with atopic mothers and none with atopic fathers had AD with onset before 6 months (P = 0.007). When all types of disease evidence (AD, recurrent wheeze and food reactions) were analysed together no significant difference was apparent between the groups. The two groups were found to be well matched with regard to breast-feeding, time of starting cow's milk, solids and egg, sex, month of birth, parental AD and smoking, race, household pets and neonatal IgE concentration. IgE concentrations at each age and the prevalence of skin prick positivity were similar between the groups. Maternal atopy poses a higher risk for infantile AD and paternal atopy. Whether this may be due to genetic or congenital factors or both is uncertain, but clearly the finding is of relevance in the prediction of allergy in childhood.

Risk of developing atopic disease after early feeding with cows' milk based formula

A follow up of a cohort of 736 healthy full term children with exposure to cows' milk based formula and breast milk from donors on the maternity ward was performed. The children were divided into three exposure groups according to the feeding patterns on the maternity ward. Group 1 received only mother's milk, group 2 mother's milk and human donors' milk, and group 3 received mother's milk, donors' milk and cows' milk based formula. The children were investigated at 7 years of age, by examining their medical files, and at 11 and 14 years, by questionnaires regarding symptoms of atopic disease. No significant differences between the three groups at follow up were found in the cumulative incidences of atopic diseases. The amount of formula given did not affect the risk of developing atopic disease. Children with a family history of such diseases ran the same risk of subsequent atopic disease whether they were fed formula or breast milk alone. Cows' milk based formula given on the maternity ward does not seem to increase the risk of developing atopic disease.

Intestinal permeability in pediatric gastroenterology

The role of the physiologic barrier function of the small bowel and its possible role in health and disease has attracted much attention over the past decade. The intestinal mucosal barrier for luminal macromolecules and microorganism is the result of non-immunologic and immunologic defense mechanisms. The non-immunologic mechanisms consist of intraluminal factors such as gastric acid, proteolytic activity, and motility and of mucosal surface factors like mucin and the microvillous membrane. The immunologic mechanisms include secretary IgA and cell-mediated immunity. Both types of mechanism are not completely mature at birth. Maturation of this barrier is not finished before the 2nd year of life. One of the aspects of the mucosal barrier function can be estimated by the intestinal permeability (IP) for macromolecules. We use the differential sugar absorption test (SAT), in which the ratio of urinary excretion of a relatively large molecule, lactulose, is compared with that of a relatively small molecule, mannitol, after oral ingestion. Although the small intestine is permeable to certain macromolecules in normal developmental conditions, an increased IP could be involved in the pathophysiology of several diseases, including infectious diarrhea, food allergy, celiac disease, and Crohn's disease. It can be concluded that IP, as measured with the SAT, reflects the state of the mucosal barrier and is altered in several gastrointestinal diseases. The SAT is a non-invasive IP test that can be of diagnostic help to demonstrate alterations in the small-mucosal barrier function and may be useful to evaluate therapeutic interventions.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrent wheezing in relation to environmental risk factors in infancy. A prospective study of 276 infants

Clinical course and environmental factors were recorded in a prospective study of 276 unselected infants followed from birth to the age of 18 months. The study was performed with a questionnaire at the age of 6 and 12 months and a physical examination at 18 months. Fifty-nine (21%) of the children had greater than or equal to 2 episodes of wheezing before they were 18 months old. A total of 58 (21%) of the children belonged to the lowest social class V, 182 (66%) were daily exposed to passive tobacco smoking at home and/or in daycare, 164 (59%) were breastfed greater than or equal to 3 months, 192 (70%) were in daycare, 62 (22%) lived in flats and 167 (61%) were in daily contact with furred pets at home and/or in daycare. In social class V a preponderance of children were exposed to passive tobacco smoking, a majority were living in flats and a minority were breastfed greater than or equal to 3 months. Linear logistic regression analysis was used for the purpose of assessing the causal effect of environmental risk factors on the risk of recurrent episodes of wheezing before the age of 18 months. The study demonstrated that male sex and daily exposure to passive tobacco smoking were significant risk factors with estimated odds ratios 1.9 and 2.4, respectively. Maternal tobacco smoking seemed to be associated with the highest risk. There was a tendency--though not significant--indicating that breastfeeding greater than or equal to 3 months had a protective effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Disturbances of essential fatty acid- and prostaglandin E-mediated immunoregulation in atopy

Impaired suppressor T lymphocyte maturation and function in atopic individuals are explained by an insufficient transmission of prostaglandin E (PGE) signals during thymic lymphocyte differentiation as well as an impaired ability of the atopic immune system to activate suppressor T-cells by PGE-mediated feed back mechanisms. We demonstrate that spontaneous in vitro immunoglobulin E synthesis of atopic peripheral blood mononuclear cells could be suppressed by the addition of 10(-6) M to 10(-5) M PGE1 or PGE2. Decreased plasma and breast milk levels of PGE-precursor fatty acids and reduced numbers of PGE2-receptors on atopic lymphocytes have been observed in atopic individuals. These insights might offer a novel approach for the prevention of atopic disease by substitution of the atopic pregnant and nursing woman and her newborn infant with long chain omega-6-fatty acids.

Relationship between IgG1 and IgG4 antibodies to foods and the development of IgE antibodies to inhalant allergens. II. Increased levels of IgG antibodies to foods in children who subsequently develop IgE antibodies to inhalant allergens

In the present investigation we have tested the hypothesis that children with a high IgG antibody response to foods have an increased risk of developing IgE antibodies to inhalant allergens. Sera from 106 children with an increased risk of developing IgE-mediated allergy were analysed. During the follow-up, in 54 of these children IgE antibodies to inhalant allergens appeared. A positive/negative IgG1 and IgG4 anti-food score was determined as described previously: sera from age-clustered unselected children were tested for the levels of IgG1 and IgG4 antibodies to common foods. For each IgG RAST and each age group, the 75-percentile was chosen as cut-off value. Each antibody level was thus converted into a positive (higher than the 75-percentile of the age group) or negative value. The number of positive tests was used as the score. High-risk children with a high IgG1 anti-food score more often developed inhalant-specific IgE antibodies than high-risk children with low IgG1 titres: 50% of the children with a high IgG1 anti-food score developed IgE antibodies to grass pollen. Fifty per cent of the children with a high and 14% of the children with a low IgG1 anti-food score developed IgE antibodies to cat dander. For the prediction of the development of IgE anti-mite (house dust mite), the IgG4 anti-food scores appeared less useful than the IgG1 anti-food scores; 46% of the IgG4 high responders versus 22% of the IgG4 low responders acquired IgE anti-mite, whereas for IgG1 these percentages were 73 and 19, respectively.

Bovine beta-lactoglobulin in human milk from atopic and non-atopic mothers. Relationship to maternal intake of homogenized and unhomogenized milk

Human milk samples (n = 300) were collected during a 3-week period from 10 healthy mothers and from 10 atopic mothers, all with healthy, solely breast-fed infants. The milk samples were analysed by an enzyme-linked immunosorbent assay (ELISA) for the content of bovine beta-lactoglobulin (BLG). In a cross-over design the atopic and non-atopic mothers alternated their intake of milk between homogenized and unhomogenized milk each week. On day 7, in each week, consecutive milk samples were taken before and 4, 8, 12 and 24 hr after a single ingestion of 500 ml of homogenized or unhomogenized milk. Detectable amounts of BLG (0.9-150 micrograms/l, median value 4.2 micrograms/l) were measured in 19/20 of the mothers (95%), in 9 of 10 atopic mothers and in all 10 of 10 non-atopic mothers. No correlation was found between the type of milk preparation (homogenized or unhomogenized) and the presence of BLG or the level of BLG in human milk. A great intra-individual and inter-individual variation of BLG level was found, and no relationship was observed between BLG levels and atopic status of the mothers. The interval between ingestion of 500 ml of milk and the maximal concentration of BLG on milk-free diet varied between 4 and 24 hr, median value 8 hr. The presence of BLG in human milk is a common finding in both atopic and non-atopic mothers.

Food allergy: facts and fiction

Hypersensitivity reactions to dietary products are especially common in the pediatric population, yet food allergy as a distinct clinical entity remains poorly defined. The clinicopathologic features of this syndrome can vary considerably from patient to patient; no reliable diagnostic laboratory tests are available, and some of the treatment regimens are controversial. The pathogenesis of this condition is not well understood. An important factor is the role of the intestinal mucosal barrier in the regulation of uptake of dietary antigen from the intestinal tract. Recently, significant differences have been observed between the features of the immature newborn and the mature adult intestinal mucosal barriers. These findings may be of fundamental importance to the pathogenesis of food allergy and are currently an area of intense research.