Brent Taylor

Measles, mumps, and rubella vaccination and bowel problems or developmental regression in children with autism: population study

Abstract Objectives: To investigate whether measles, mumps, and rubella (MMR) vaccination is associated with bowel problems and developmental regression in children with autism, looking for evidence of a “new variant” form of autism. Design: Population study with case note review linked to independently recorded vaccine data. Setting: Five health districts in north east London. Participants: 278 children with core autism and 195 with atypical autism, mainly identified from computerised disability registers and born between 1979 and 1998. Main outcome measures: Recorded bowel problems lasting at least three months, age of reported regression of the childs development where it was a feature, and relation of these to MMR vaccination. Results: The proportion of children with developmental regression (25% overall) or bowel symptoms (17%) did not change significantly (P value for trend 0.50 and 0.47, respectively) during the 20 years from 1979, a period which included the introduction of MMR vaccination in October 1988. No significant difference was found in rates of bowel problems or regression in children who received the MMR vaccine before their parents became concerned about their development (where MMR might have caused or triggered the autism with regression or bowel problem), compared with those who received it only after such concern and those who had not received the MMR vaccine. A possible association between non-specific bowel problems and regression in children with autism was seen but this was unrelated to MMR vaccination. Conclusions: These findings provide no support for an MMR associated “new variant” form of autism with developmental regression and bowel problems, and further evidence against involvement of MMR vaccine in the initiation of autism. What is already known on this topic A “new variant” form of autism has been hypothesised, associated with developmental regression and bowel problems and caused or triggered by the MMR vaccination This postulated association along with media attention has had a major adverse effect on public confidence in the vaccine Although population studies have shown no association between autism and MMR vaccine it has been further postulated that various environmental or genetic cofactors are required for the effect What this study adds The proportion of children with autism who had developmental regression or bowel problems has not changed over the 20 years from 1979 Neither developmental regression nor bowel problems in children with autism was associated with MMR vaccination No evidence was found for a “new variant” form of autism

CHANGES IN THE REPORTED PREVALENCE OF CHILDHOOD ECZEMA SINCE THE 1939-45 WAR

Rates of reported eczema during early childhood were studied in 3 national cohorts of children born in 1946, 1958, and 1970. Overall rates rose from 5.1% in children born in 1946, to 7.3% in those born in 1958, to 12.2% in the 1970 cohort. In the 1958 and 1970 cohorts there was a positive association between eczema and breastfeeding. This relationship remained significant after allowing for parental history of allergy and socioeconomic status. Social classes I and II children born in 1946 were less likely to be reported as having eczema, compared with children from lower social classes, whereas children born into higher social classes in 1958 and 1970 had higher rates. These findings may reflect secular changes in the diagnosis of eczema or may represent a real increase in the disorder. The positive association with breastfeeding in the more recent cohorts suggests a new environmental agent may be crossing in breast-milk. The agent(s) may well be in other infant foods, since the rate of reported eczema in non-breastfed children rose from 5.7% in the 1946 and 1958 cohorts to 11.1% of children born in 1970.

TRANSIENT IgA DEFICIENCY AND PATHOGENESIS OF INFANTILE ATOPY

Abstract IgA deficiency at 3 months was associated with the development of atopy (eczema and positive prick tests) within the first year in the offspring of reaginic parents. At 1 year the IgA levels were higher in the atopic than the non-atopic infants. These findings suggest that a brief period of allergen avoidance during a symptomfree vulnerable period might prevent much atopic disease.

Thimerosal Exposure in Infants and Developmental Disorders: A Retrospective Cohort Study in the United Kingdom Does Not Support a Causal Association

Objective. After concerns about the possible toxicity of thimerosal-containing vaccines in the United States, this study was designed to investigate whether there is a relationship between the amount of thimerosal that an infant receives via diphtheria-tetanus-whole-cell pertussis (DTP) or diphtheria-tetanus (DT) vaccination at a young age and subsequent neurodevelopmental disorders. Methods. A retrospective cohort study was performed using 109 863 children who were born from 1988 to 1997 and were registered in general practices in the United Kingdom that contributed to a research database. The disorders investigated were general developmental disorders, language or speech delay, tics, attention-deficit disorder, autism, unspecified developmental delays, behavior problems, encopresis, and enuresis. Exposure was defined according to the number of DTP/DT doses received by 3 and 4 months of age and also the cumulative age-specific DTP/DT exposure by 6 months. Each DTP/DT dose of vaccine contains 50 μg of thimerosal (25 μg of ethyl mercury). Hazard ratios (HRs) for the disorders were calculated per dose of DTP/DT vaccine or per unit of cumulative DTP/DT exposure. Results. Only in 1 analysis for tics was there some evidence of a higher risk with increasing doses (Coxs HR: 1.50 per dose at 4 months; 95% confidence interval [CI]: 1.02–2.20). Statistically significant negative associations with increasing doses at 4 months were found for general developmental disorders (HR: 0.87; 95% CI: 0.81–0.93), unspecified developmental delay (HR: 0.80; 95% CI: 0.69–0.92), and attention-deficit disorder (HR: 0.79; 95% CI: 0.64–0.98). For the other disorders, there was no evidence of an association with thimerosal exposure. Conclusions. With the possible exception of tics, there was no evidence that thimerosal exposure via DTP/DT vaccines causes neurodevelopmental disorders.

MMR and autism: further evidence against a causal association

The hypothesis that MMR vaccines cause autism was first raised by reports of cases in which developmental regression occurred soon after MMR vaccination. A previous study found no evidence to support this hypothesis. It has recently been suggested that MMR vaccine might cause autism, but that the induction interval need not be short. The data from the earlier study were reanalysed to test this second hypothesis. Our results do not support this hypothesis, and provide further evidence against a causal association between MMR vaccination and autism.

Idiopathic thrombocytopenic purpura and MMR vaccine

A CAUSAL ASSOCIATION BETWEEN MEASLES mumps–rubella (MMR) vaccine and idiopathic thrombocytopenic purpura (ITP) was confirmed using immunisation/hospital admission record linkage. The absolute risk within six weeks of immunisation was 1 in 22 300 doses, with two of every three cases occurring in the six week post-immunisation period being caused by MMR. Children with ITP before MMR had no vaccine associated recurrences.

Parental smoking and lower respiratory illness in the first three years of life.

The relationships between parental smoking and the rates of lower respiratory illness during the first three years of life were examined for a birth cohort of 1265 New Zealand children. Lower respiratory illness varied significantly with maternal smoking for the first year; there was equivocal evidence of a relationship between maternal smoking and lower respiratory illness in the second year; and by third year the relationship had clearly disappeared. Paternal smoking had no significant effect on rates of lower respiratory illness at any time. Application of logistic regression showed that for the first year rates of lower respiratory illness were approximately linearly related to maternal smoking: increases of five cigarettes a day resulted in an increase of 2.5 to 3.5 incidents of lower respiratory illness per 100 children at risk. Statistical control for maternal age, education, family size, and family living standards showed that the relationship between maternal smoking and rates of lower respiratory illness was not significantly influenced by these factors.

Predisposing factors and the development of reaginic allergy in infancy.

In a prospective study of fifty‐eight newborn infants of parents with reaginic allergy, twenty‐seven developed eczema and twenty‐eight positive prick tests to one or more of six antigens during the first year of life. These reaginic manifestations were related to presymptomatic transient IgA deficiency. The development of positive skin tests was also related to HLA A1 B8, and to season of birth. The order of frequency of positivity was Dermatophagoides, grass pollens, cat fur, feathers and cows milk. The skin tests were often positive in infants in whom serum IgE was not detected. The eczema disappeared and the skin tests became negative in some infants at the end of the first year. This work suggests that sensitization in the new‐born period is important in the subsequent development of disease.

Eczema and infant diet

The relationship between parental atopy, breast‐feeding, early solid food diet and the rate of eczema was studied in a birth cohort of 2‐year‐old children. Rates of eczema varied significantly with parental atopy and solid feeding: children of atopic parents given solid food during the first 4 months had over two‐and‐a‐half times the rate of eczema of children not given solid food and who had non‐atopic parents. Further, rates of eczema increased in almost direct proportion to the number of different types of solid food that the child had been given during the first 4 months. Breast‐feeding had no significant effect on rates of eczema.

Adult Health and Social Outcomes of Children Who Have Been in Public Care: Population-Based Study

Objective. To examine adult socioeconomic, educational, social, and health outcomes of being in public care in childhood. Methods. The 1970 British birth cohort was followed up at 5 (N = 13135), 10 (14875), 16 (11622), and 30 years (11261). Cases were defined as those ever in statutory or voluntary public care at 5, 10, and 16 years. Self-reported adult outcomes were occupation, educational achievement, general health, psychological morbidity, history of homelessness, school exclusion, and convictions. Results. A total of 343 (3.6%) of 9557 had been in public care <17 years. Nonwhite children were more likely to have been in care (odds ratio [OR]: 3.3; 95% confidence interval [CI]: 2.1–5.4). Controlling for socioeconomic status, men with a history of public care were less likely to attain high social class (OR: 0.6; 95% CI: 0.4–0.9) and more likely to have been homeless (OR: 2.0; 95% CI: 1.1–3.8), have a conviction (OR: 2.3; 95% CI: 1.5–3.4), have psychological morbidity (OR: 1.8; 95% CI: 1.1–3.0), and be in poor general health (OR: 1.6; 95% CI: 1.1–2.6). Similar associations were found in women. Men but not women with a history of care were more likely to be unemployed (OR: 2.6; 95% CI: 1.4–5.0) and less likely to attain a higher degree (OR: 0.4; 95% CI: 0.2–0.7). Nonwhite ethnicity was associated with poorer adult outcomes of being in care. Conclusions. Public care in childhood is associated with adverse adult socioeconomic, educational, legal, and health outcomes in excess of that associated with childhood or adult disadvantage.