Parental socioeconomic status and risk of offspring autism spectrum disorders in a Swedish population-based study

Low maternal progesterone may contribute to both obstetrical complications and autism

Studies show increased autism risk among children born to mothers experiencing obstetrical complications. Although this is usually interpreted as suggesting that the obstetrical complications could be causing autism, it is possible that a single factor could be responsible for both complications and autism. We hypothesized that low levels of the hormone progesterone is responsible since it is supplied to the fetus maternally and does not only support pregnancy but also promotes brain development. Following a review of the literature, we report findings from a survey of mothers of autistic children (n=86) compared to mothers of typically-developing children (n=88) regarding obstetrical histories, including five obstetrical risk factors indicative of low progesterone. Using this analysis, the ASD group had significantly more risk factors than controls (1.21 ± 0.09 vs. 0.76 ± 0.08, p<.0001), suggesting low progesterone. Thus, results suggest that low progesterone may be responsible for both obstetrical complications and brain changes associated with autism and that progesterone levels should be routinely monitored in at-risk pregnancies. Our hypothesis also suggests that ensuring adequate levels of progesterone may decrease the likelihood of autism.

Addressing the inverse care law: the role of community paediatric services

BACKGROUND

Children's health suffers disproportionately from the effects of poverty. The inverse care law states that those who need care the most are the least likely to receive it. Community paediatricians are well placed to address health inequalities in children.

AIMS

To explore, using routinely collected data, whether we address health inequalities and the inverse care law, particularly for certain conditions targeted by our specialty.

METHODS

Five years of data were analysed, during which health equity audits have led to service changes in order to tackle inequities. The data include postcodes, allowing each child to be assigned to a deprivation quintile, and a range of diagnoses, including five sentinel conditions: attention deficit hyperactivity disorder (ADHD) on medication, autistic spectrum disorder (ASD), epilepsy, cerebral palsy and Down's syndrome. This allowed analysis of the caseload by deprivation index for these conditions, comparison with the background population and exploration of time trends.

RESULTS

The number of children on the caseload and their distribution across the quintiles remained stable. The proportion of deprived children (i.e. in the lowest two quintiles) on the caseload over the last five years taken together is 56%, compared to 44% in the background population. The numbers of children with ADHD on medication has almost quadrupled in deprived quintiles and doubled in the least deprived quintile, while the numbers of children with this diagnosis in the most deprived is four times that in the least deprived. Numbers of children with ASD have also increased in each quintile. In contrast, the number of children with epilepsy and cerebral palsy did not show much variation, but those from deprived quintiles made up a greater proportion of the caseload.

CONCLUSIONS

Routine data collection demonstrates that inequalities are addressed using all four quality domains of service provision and sentinel conditions more likely to affect deprived children are targeted. We believe it is possible for all services to collect and analyse data thus with minimal effort, thereby providing a foundation from which to address the inverse care law.

Parental age and the risk of autism spectrum disorders: findings from a Swedish population-based cohort

BACKGROUND

The objectives of this study were to examine the independent and dependent associations of maternal and paternal age and risk of offspring autism spectrum disorders (ASD), with and without intellectual disability (ID).

METHODS

The sample consisted of 417 303 Swedish children born 1984-2003. ASD case status (N = 4746) was ascertained using national and regional registers. Smoothing splines in generalized additive models were used to estimate associations of parental age with ASD.

RESULTS

Whereas advancing parental age increased the risk of child ASD, maternal age effects were non-linear and paternal age effects were linear. Compared with mothers at the median age 29 years, those <29 had similar risk, whereas risk increased after age 30, with an odds ratio (OR) of 1.75 [95% (CI): 1.63-1.89] at ages 40-45. For fathers, compared with the median age of 32 years, the OR for ages 55-59 was 1.39 (1.29-1.50). The risk of ASD was greater for older mothers as compared with older fathers. For example, mothers aged 40-45 (≥97.2th percentile) had an estimated 18.63 (95% CI: 17.25-20.01) ASD cases per 1000 births, whereas fathers aged 55-59 (≥99.7th percentile) had 16.35 (95% CI: 15.11-17.58) ASD cases per 1000 births. In analyses stratified by co-parental age, increased risk due to advancing paternal age was evident only with mothers ≤35 years. In contrast, advancing maternal age increased risk regardless of paternal age. Advancing parental age was more strongly associated with ASD with ID, compared with ASD without ID.

CONCLUSIONS

We confirm prior findings that advancing parental age increases risk of ASD, particularly for ASD with ID, in a manner dependent on co-parental age. Although recent attention has emphasized the effects of older fathers on ASD risk, an increase of n years in maternal age has greater implications for ASD risk than a similar increase in paternal age.

Translational toxicology: a developmental focus for integrated research strategies

BACKGROUND

Given that toxicology studies the potential adverse effects of environmental exposures on various forms of life and that clinical toxicology typically focuses on human health effects, what can and should the relatively new term of "translational toxicology" be taken to mean?

DISCUSSION

Our assertion is that the core concept of translational toxicology must incorporate existing principles of toxicology and epidemiology, but be driven by the aim of developing safe and effective interventions beyond simple reduction or avoidance of exposure to prevent, mitigate or reverse adverse human health effects of exposures.The field of toxicology has now reached a point where advances in multiple areas of biomedical research and information technologies empower us to make fundamental transitions in directly impacting human health. Translational toxicology must encompass four action elements as follows: 1) Assessing human exposures in critical windows across the lifespan; 2) Defining modes of action and relevance of data from animal models; 3) Use of mathematical models to develop plausible predictions as the basis for: 4) Protective and restorative human health interventions. The discussion focuses on the critical window of in-utero development.

SUMMARY

Exposure assessment, basic toxicology and development of certain categories of mathematical models are not new areas of research; however overtly integrating these in order to conceive, assess and validate effective interventions to mitigate or reverse adverse effects of environmental exposures is our novel opportunity. This is what we should do in translational toxicology so that we have a portfolio of interventional options to improve human health that include both minimizing exposures and specific preventative/restorative/mitigative therapeutics.

Parental depression, maternal antidepressant use during pregnancy, and risk of autism spectrum disorders: population based case-control study

OBJECTIVE

To study the association between parental depression and maternal antidepressant use during pregnancy with autism spectrum disorders in offspring.

DESIGN

Population based nested case-control study.

SETTING

Stockholm County, Sweden, 2001-07.

PARTICIPANTS

4429 cases of autism spectrum disorder (1828 with and 2601 without intellectual disability) and 43,277 age and sex matched controls in the full sample (1679 cases of autism spectrum disorder and 16,845 controls with data on maternal antidepressant use nested within a cohort (n=589,114) of young people aged 0-17 years.

MAIN OUTCOME MEASURE

A diagnosis of autism spectrum disorder, with or without intellectual disability.

EXPOSURES

Parental depression and other characteristics prospectively recorded in administrative registers before the birth of the child. Maternal antidepressant use, recorded at the first antenatal interview, was available for children born from 1995 onwards.

RESULTS

A history of maternal (adjusted odds ratio 1.49, 95% confidence interval 1.08 to 2.08) but not paternal depression was associated with an increased risk of autism spectrum disorders in offspring. In the subsample with available data on drugs, this association was confined to women reporting antidepressant use during pregnancy (3.34, 1.50 to 7.47, P=0.003), irrespective of whether selective serotonin reuptake inhibitors (SSRIs) or non-selective monoamine reuptake inhibitors were reported. All associations were higher in cases of autism without intellectual disability, there being no evidence of an increased risk of autism with intellectual disability. Assuming an unconfounded, causal association, antidepressant use during pregnancy explained 0.6% of the cases of autism spectrum disorder.

CONCLUSIONS

In utero exposure to both SSRIs and non-selective monoamine reuptake inhibitors (tricyclic antidepressants) was associated with an increased risk of autism spectrum disorders, particularly without intellectual disability. Whether this association is causal or reflects the risk of autism with severe depression during pregnancy requires further research. However, assuming causality, antidepressant use during pregnancy is unlikely to have contributed significantly towards the dramatic increase in observed prevalence of autism spectrum disorders as it explained less than 1% of cases.

Prenatal and early life exposure to stressful life events and risk of autism spectrum disorders: population-based studies in Sweden and England

Background and Aim

Exposure to stressful life events during pregnancy has been suggested as a potential risk factor for offspring Autism Spectrum Disorders (ASD), but the literature is limited and inconsistent. We tested the hypothesis that maternal exposure to stressful life events would be associated with increased risks of offspring ASD, and that these risks would be highest for exposures during the prenatal period.

Methods and Results

We used prospectively collected data from two large population based studies in Sweden and England. In the Swedish study of 4429 ASD cases and 43277 controls, our exposure comprised the occurrence of any severe life event before and during pregnancy and the child's early life. In the English study (maximum n = 11554, ASD n = 72), we studied the risk of offspring ASD in relation to a combined maternal exposure to multiple (up to 42) common and rare life events, as well as their perceived impact upon the mother during pregnancy and early life. In crude and adjusted regression analyses in both studies, we found no evidence of an association between prenatal life events, or their number and perceived impact and the risk of offspring ASD. Sub-group analysis of ASD with and without intellectual disability in the Swedish study yielded similar results.

Conclusion

We found no evidence to support the hypotheses that exposure to stressful life events during the prenatal period is associated with an increased risk of offspring ASD.