Search PubMed⌕ Search

Biomedical subjects

S Halken

Publications and source records attributed to S Halken.

At least 19 recordsLinked to original sources
PubMed2001

Prevention.

The development of food allergy depends on several factors, including genetic factors and early exposure to allergenic proteins in the diet, food protein uptake and handling, and the development of tolerance. Many hypotheses, as regards the possible causal relationships, have been raised during the past few years, including the hygiene theory, the role of bacterial gut flora, and the potential effect of different cytokines in breast milk. Although interesting, these are mainly speculations based on non-interventional and often retrospective/cross-sectional studies including small study populations. These theories remain to be documented in proper, controlled and prospective studies. Breastfeeding and the late introduction of solid foods (>4 months) is associated with a reduced risk of food allergy, atopic dermatitis, and recurrent wheezing and asthma in early childhood. In all infants, breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation. Preventive dietary restrictions after the age of 4-6 months are not scientifically documented.

Breast Feeding↗
PubMed2000

Comparison of a partially hydrolyzed infant formula with two extensively hydrolyzed formulas for allergy prevention: a prospective, randomized study.

The aim of this study was to compare the allergy-preventive effect of a partially hydrolyzed formula with two extensively hydrolyzed formulas, in infants with a high risk for development of allergic disease. High-risk infants from four Danish centres were included in the period from June 1994 to July 1995. Five-hundred and ninety-five high-risk infants were identified. High-risk infants were defined as having biparental atopy, or a single atopic first-degree relative combined with cord blood immunoglobulin E (IgE)> or =0.3 kU/l. At birth all infants were randomized to one of three different blinded formulas. All mothers had unrestricted diets during pregnancy and lactation and were encouraged to breast-feed exclusively. If breast-feeding was insufficient, one of the three formulas, according to randomization, was given during the first 4 months. It was recommended not to introduce cow's milk, cow's milk products. and solid foods until the age of 4 months. After the age of 4 months a normal unrestricted diet and conventional cow's milk-based formula were given when needed. All infants were followed-up prospectively with interview and physical examination at the age of 6, 12, and 18 months, and if any possible atopic symptoms were reported. If food allergy was suspected, controlled elimination/challenge procedures were performed in a hospital setting. Of 550 infants included in the study, 514 were seen at all visits and 36 were excluded owing to noncompliance. Of 478 infants who completed the study, 232 were exclusively breast-fed, 79 received an extensively hydrolyzed casein formula (Nutramigen), 82 an extensively hydrolyzed whey formula (Profylac), and 85 a partially hydrolyzed whey formula (Nan HA), during the first 4 months of life. These four groups were identical in regard to atopic predisposition, cord blood IgE, birthplace, and gender. Exclusively breast-fed children were exposed less to tobacco smoke and pets at home and belonged to higher social classes, whereas the three formula groups were identical concerning environmental factors. The frequency of breast-feeding was high; only eight (2%) children were not breast-fed at all. The three formula groups were identical in regard to duration of breast-feeding and age at introduction of formula and solid foods. No significant differences were found in the three groups of infants receiving formula milk regarding the cumulative incidence of atopic dermatitis or respiratory symptoms. The cumulative incidence of parental-reported cow's milk allergy was significantly higher in children fed partially hydrolyzed formula (Nan HA) compared with extensively hydrolyzed formula (Nutramigen or Profylac) at 12 and 18 months (NanHA, 7.1%; Nutramigen, 2.5%; Profylac, 0%; p=0.033). The cumulative incidence of confirmed cow's milk allergy was 1.3% (three of 232) in exclusively breast-fed infants, 0.6% (one of 161) in infants fed extensively hydrolyzed formula (Nutramigen or Profylac), and 4.7%(four of 85) in infants fed partially hydrolyzed formula (Nan HA). Partially hydrolyzed formula was found to be less effective than extensively hydrolyzed formula in preventing cow's milk allergy, 0.6% vs. 4.7% (p=0.05), but because of the small number of cases the results should be interpreted with caution. Compared with other similar studies the frequency ofatopic symptoms was low, even though the dietetic intervention did not include either maternal diet during lactation or dietary restrictions to the children after the age of 4 months.

Breast Feeding↗
PubMed1995

Increased proportions of bacteria capable of cleaving IgA1 in the pharynx of infants with atopic disease.

Based on the observation that children with a history of atopic disease show significantly increased levels of cleaved secretory IgA in nasopharyngeal secretions, we have previously formulated the hypothesis that bacteria-induced local deficiencies of the immune barrier of the upper respiratory tract may be a contributing factor in the development and perpetuation of atopic diseases. To evaluate this hypothesis, 25 infants were subjected to clinical, bacteriologic, and immunologic examination at the age of 18 mo, 30 mo, and 5 y. The 11 infants, who showed clinical and immunologic evidence of atopic disease at the age of 18 mo, harbored significantly higher proportions of IgA1 protease-producing bacteria (median, 36%; range, 14-64%) than the 14 healthy infants (median, 5%; range, 0.4-14%). No statistically significant differences were observed at the two subsequent examinations, but healthy children showed a statistically significant increase in proportions of IgA1 protease-producing bacteria in the pharynx with increasing age. IgA1 protease-producing bacteria detected included Streptococcus mitis biovar 1, Haemophilus influenzae, Haemophilus parahaemolyticus, Streptococcus pneumoniae, and Neisseria meningitidis, of which the first mentioned species was mainly responsible for the difference observed at the 18-mo examination. Percentage proportions of IgA1 protease-producing bacteria were significantly related to passive smoking which may stimulate the premature and more pronounced pharyngeal colonization of the atopic infants with the IgA1 protease-producing variant of S. mitis biovar 1. The results of the study support the hypothesis that IgA1 protease-producing bacteria colonizing the upper respiratory tract jeopardize the local immune barrier and, thereby, may facilitate the penetration of potential allergens resulting in atopic disease.

Bacterial Infections↗
PubMed1995

The natural history of cow's milk protein allergy/intolerance.

In prospective studies th incidence of cow's milk protein allergy and intolerance (CMPA/CMPI) in infancy in western industrialized countries has been estimated to be about 2-3% based on strict diagnostic criteria. A significant association between early neonatal exposure to cow's milk formula feeding and subsequent development of CMPA/CMPI has been documented. The small amounts of 'foreign' protein in human milk may rather induce tolerance than allergic sensitization. The findings of specific IgE to individual cow's milk proteins in cord blood of the majority of infants who later develop CMPA/CMPI suggests a prenatal sensitization may play a role in the pathogenesis of CMPA/CMPI. Perhaps a weak intrauterine education of low IgE-response may need to 'boosted' neonatally in order to cause clinical disease. The prognosis of CMPA/CMPI is good with a recovery of about 45-56% at one year, 60-77% at two years and 71-87% at three years. Associated adverse reactions to other foods, especially egg, soy, peanut and citrus develop in about 41-54%. Allergy to potential environmental inhalant allergens has been reported in up to 28% by three years and up to 80% before the age of puberty. Especially, infants with an early increased IgE response to cow's milk protein have an increased risk of persisting CMPA, development of persistent adverse reactions to other foods and development of allergy against environmental inhalant allergens. Cow's milk protein/intolerance (CMPA/CMPI), meaning reproducible adverse reactions to cow's milk protein(s) may be due to the interaction between one or more milk proteins and one or more immune mechanisms, possible any of the four basic types of hypersensitivity reactions. Immunologically mediated reactions are defined as CMPA. Mostly, CMPA is caused by IgE-mediated (type I) reactions, but evidence for type III (immune complex) reactions and type IV (cell mediated reactions) have been demonstrated as reviewed by Høst (1994) and Ortolani & Vighi (1995). Non immunologically reactions against cow's milk protein(s) are defined as CMPI. However, it should be stressed that many studies on 'cow's milk allergy' have not investigated the immunological basis of the clinical reactions. In most instances of cow's milk protein hypersensitivity only diagnostic investigations such as skin prick test and RAST indicative of IgE-mediated reactions are performed. In fact, CMPA cannot be ruled out unless extensive diagnostic tests for type II-III-IV reactions have proved negative. Thus, the classification of adverse reactions to cow's milk proteins depends on the extent and the quality of performed diagnostic tests for immune mediated reactions. At present, no single laboratory test is diagnostic of CMPA/CMPI, and differentiation between CMPA and CMPI cannot be based solely on clinical symptoms. Therefore the diagnosis has to be based on strict well-defined elimination and milk challenge procedure (Hill & Hosking, 1991), (Høst, 1994). Preferably, double-blind placebo-controlled challenges (DBPCFC) should be carried out in children older than 1-2 years of age. In infants open controlled challenges have been shown to be reliable when performed under professional observation in a hospital setting (Høst & Halken, 1990).

Child, Preschool↗
PubMed1995

The effect of hypo-allergenic formulas in infants at risk of allergic disease.

Development of atopic disease seems to depend on both genetic factors and exposure to several environmental factors. At present ther is evidence that the mode of early infant feeding influences the development of food allergy, whereas daily exposure to inhalant allergens and daily exposure to tobacco smoke is found to be associated with an increased risk of recurrent wheezing/asthma and inhalant allergy. In infants with atopic predisposition (first-degree relatives), exclusively breastfeeding > or = four months is found associated with a significant reduction of the cumulative prevalence of cow's milk allergy/intolerance (CMA/CMI) during the first 1-2 years of age. When breastmilk is insufficient or lacking a substitute formula is needed. Several recent prospective studies show a preventative effect of extensively hydrolysed formula (eHF) in combination with avoidance of cow's milk proteins and solid foods during > or = 4 months in high-risk infants on the cumulative prevalence of food allergy and atopic dermatitis during the first 2-4 years of life. Partially hydrolysed formulas (pHF) may be effective in allergy prevention, but due to drawbacks of study design and lack of documentation pHF cannot be recommended at present. The results of studies comparing the preventive effect of eHF and pHF are awaited. The protective effect on the development of cow's milk allergy is a real prevention and not only a postponement of the onset of symptoms. No studies have demonstrated a preventive effect of dietary measures as regards asthma/inhalant allergy, at present until the age of four years. As no studies concerning the preventive effect of avoidance of milk and other foods after the age of 4-6 months of life have been performed, recommendation of preventive elimination diets beyond this age is empirically based. In order to reduce the costs, to minimize the risk of stigmatisation and the risk of malnutrition it is important to avoid unnecessary restrictive and prolonged diets. A diet period of 4-6 months seems sufficient in most infants. At present eHF are recommended for avoidance of cow's milk. Some high risk infants may benefit from maternal diet during lactation, but there is no documented beneficial effect of maternal diet during pregnancy.

Breast Feeding↗
PubMed1994

[Prevention of allergy in infants. A prospective study of 159 high-risk children].

A total of 105 infants at "high risk" for developing allergy born in 1988 were studied prospectively from birth to 18 months of age. The infants were recommended breastfeeding and/or hypoallergenic formula (Nutramigen or Profylac) combined with avoidance of solid foods the first six months of life. All mothers had unrestricted diet. Avoidance of daily exposure to tobacco smoking, furred pets and dust collecting materials in the bedroom was advised. This prevention group was compared to a control group consisting of 54 identically defined "high-risk" infants born in 1985 in the same area. All the infants had either severe single atopic predisposition combined with cord blood IgE > or = 0.5 KU/l or biparental atopic predisposition. The control group had unrestricted diet and was not advised about environmental factors. The cumulative incidence of atopic symptoms was significantly lower at 18 months in the prevention group (32%) compared with the control group (74%) (p < 0.01), due to reduced incidence of recurrent wheezing (13% versus 37%; p < 0.01), atopic dermatitis (14% versus 31%; p < 0.01), vomiting/diarrhoea (5% versus 20%; p < 0.01) and infantile colic (9% versus 24%; p < 0.01). The cumulative incidence of food-allergy was significantly lower in the prevention group (6% versus 17%; p < 0.05). In both high-risk groups exposure to daily tobacco smoking increased the risk of recurrent wheezing significantly (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗
PubMed1994

Adverse reactions to food additives in children with atopic symptoms.

In a multicenter study conducted at four Danish hospital pediatric departments, the parents of 472 consecutive children were informed of this project to determine the incidence of intolerance of food additives among children referred to an allergy clinic with symptoms of asthma, atopic dermatitis, rhinitis, or urticaria. After a 2-week period on an additive-free diet, the children were challenged with the eliminated additives. The food additives investigated were coloring agents, preservatives, citric acid, and flavoring agents. Carbonated "lemonade" containing the dissolved additives was used for the open challenge. Two doses were used: a low dose and a 10-fold higher dose. Gelatin capsules were used for a double-blind challenge. The children were 4-15 years old, and they were attending an outpatient pediatric clinic for the first time. Of the 379 patients who entered the study, 44 were excluded and 335 were subjected to open challenge. A total of 23 children developed positive reactions after the open challenge. Sixteen of these patients accepted the double-blind challenge, and six showed a positive reaction to preservatives (atopic dermatitis, asthma, rhinitis), coloring agents (atopic dermatitis, asthma, urticaria, gastrointestinal symptoms), and citric acid (atopic dermatitis, gastrointestinal symptoms). The incidence of intolerance of food additives was 2% (6/335), as based on the double-blind challenge, and 7% (23/335), as based on the open challenge with lemonade. Children with atopic skin symptoms had a statistically increased risk of a positive reaction. This may have consequences for the future clinical investigation of children with atopic cutaneous symptoms.

Adolescent↗
PubMed1993

Prediction of allergy from family history and cord blood IgE levels. A follow-up at the age of 5 years. Cord blood IgE. IV.

Screening of total IgE in 1189 cord blood samples was conducted by Phadebas IgE PRIST in a one-year birth cohort 1983-1984 in Viborg, Denmark. 113 children with cord blood IgE levels > or = 0.5 kU/l and 138 children chosen at random among those with cord blood IgE levels < 0.5 kU/l were seen at a follow-up at 5 years of age. Based upon history and physical examination a diagnosis of definite atopy or no atopy was established. Allergy (IgE mediated) was defined as atopic disease combined with increased total IgE levels at 5 years of age. The cumulative prevalence of atopic disease was not influenced by cord blood IgE levels or atopic predisposition. Cord blood IgE levels had a low sensitivity as a predictor of atopic disease. A statistically significant correlation between serum levels of IgE at birth and at 5 years was however found (p < 0.001), and a significantly greater number of children with elevated cord blood IgE levels developed allergic disease before 5 years of age (p < 0.01). A cut-off limit of 0.3 kU/l was superior to the originally suggested limit of 0.5 kU/l. A total IgE level > 63 kU/l (geometric mean + 1 SD) at the age of 5 years can be regarded as being an elevated level. A cord blood IgE level > or = 0.3 kU/l in combination with atopic predisposition was predictive of allergic disease, especially allergic bronchial asthma. With regard to allergic disease, the positive predictive value was 26%, the sensitivity 33% and the rate ratio for development of allergic disease 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

Safety of a new, ultrafiltrated whey hydrolysate formula in children with cow milk allergy: a clinical investigation.

The purpose of this study was to determine whether a new ultrafiltrated whey hydrolysate infant formula, Profylac, could be administered safely to children with cow milk protein allergy/intolerance. Profylac has a stated molecular weight of < 8 kD and at least 30,000 times reduced antigenicity which is controlled by a combination of ELISA-techniques and immunochemical methods. The study comprised 66 children with cow milk protein allergy/intolerance diagnosed by controlled elimination/challenge procedures. The children were aged 1 month-14.5 years, median 1 11/12 years and 15 were below 1 year. Thirty-five of these children had proven IgE-mediated reactions (cow milk protein allergy). Sixty-one of the children had at least two different symptoms and 31 had concomitant allergies to other foods and/or inhalants. All 66 children underwent and tolerated open, controlled challenges with Profylac. A total of 64 children continued having Profylac daily for at least 3 months and 58 for at least 6 months after challenge. Nine of the children older than 1 year did not like the taste and only had Profylac in minor amounts. No side effects were registered. Fifteen of the infants were below 1 year of age, and this group was compared with an age matched group of 16 infants challenged with and fed an extensively hydrolysed casein hydrolysate, Nutramigen. All the infants in these two groups accepted and tolerated Profylac and Nutramigen, respectively, and no side effects were registered. Among the 35 patients with IgE-mediated reactions 6% (2/35) had positive skin prick tests and 11% (3/28) had specific IgE class 2 against Profylac, 2 of the latter before intake of Profylac.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Preventive effect of feeding high-risk infants a casein hydrolysate formula or an ultrafiltrated whey hydrolysate formula. A prospective, randomized, comparative clinical study.

In a prospective study of a 1-year birth cohort of 158 high-risk infants the effect of feeding breastmilk, a casein hydrolysate (Nutramigen) or a new ultrafiltrated whey hydrolysate (Profylac) on the development of cow milk protein allergy/intolerance (CMPA/CMPI) was assessed and compared. All the infants had biparental or severe single atopic predisposition, the latter combined with cord blood IgE > or = 0.5 kU/L. At birth all infants were randomized to Nutramigen or Profylac, which was used when breastfeeding was insufficient or not possible during the first 6 months of life. During the same period this regimen was combined with avoidance of solid foods and cow milk protein. All mothers had unrestricted diets and were encouraged to do breastfeeding only. Moreover, avoidance of daily exposure to tobacco smoking, furred pets and dust-collecting materials in the bedroom was advised. The infants were followed prospectively from birth to 18 months of age. All possible atopic symptoms were registered and controlled elimination/challenge studies were performed when symptoms suggested CMPA/CMPI. A total of 154 (97%) were followed up and 141 followed the diet strictly. Eighty-eight (62%) of the infants were breastfed for at least 6 months, 20 (14%) were breastfed exclusively, 59 and 62 had varying amounts of Nutramigen or Profylac respectively. CMPA/CMPI was diagnosed in 1/20, 1/59 and 3/62 in the breastfed, the Nutramigen and Profylac groups respectively, but 1 of the latter also had Nutramigen. None of the infants showed reactions against Nutramigen or Profylac. In 4 infants symptoms were provoked by breastmilk when the mother ingested cow milk and in 1 only by cow milk.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗