Focused investigations regarding mortality rates, risk factors, and cause of death in autistic populations remain scarce. The present study used large linked datasets spanning 2001-2015 to report the rates and risk factors for mortality and cause of death in individuals on the autism spectrum (n = 35,929 age range 5-64) with and without concurrent intellectual disability (ID) in New South Wales, Australia. Mortality rates for those on the autism spectrum were 2.06 times that of the general population. Concurrent ID, epilepsy, mental health conditions, and chronic physical health conditions were associated with a higher risk of death for those on the spectrum, whereas demographic variables such as gender and socioeconomic status were not. A differing profile of top causes of death was found for autistic individuals relative to the general population, with "nervous system and sense disorders" and "injury and poisoning" being the top-ranked causes for those on the spectrum. The findings alert the need for health promotion and management of concurrent physical and mental health conditions for those on the autism spectrum. There is also a need for better identification, diagnosis, and documentation of older adults on the autism spectrum. Autism Res 2019, 12: 806-815.Lay Summary: Rates of death are higher for autistic individuals compared to the general population. There is higher risk of death for autistic individuals who have additional mental and physical health conditions. The leading causes of death for autistic individuals with and without ID are "nervous system and sense disorders", which includes epilepsy and "injury and poisoning", respectively. To minimize risk of death, it is important to manage the mental and physical health individuals on the autism spectrum and to better understand the circumstances surrounding preventable deaths for this population.

Anxiety is present in high rates in both children and adults on the autism spectrum. An increasing number of studies have highlighted the potentially important role that intolerance of uncertainty may have in anxiety for those on the spectrum, as well as their interrelationships with sensory sensitivities and repetitive behaviours. In response to a lack of studies involving adults, this study examined self-report survey data regarding intolerance of uncertainty, sensory sensitivities, repetitive behaviours and anxiety in a sample of 176 adults on the autism spectrum (mean age = 42). Intolerance of uncertainty and anxiety were both found to be elevated relative to non-autistic adults ( N = 116) and significant, positive correlations were found between intolerance of uncertainty, anxiety, repetitive behaviours and sensory sensitivities in those on the spectrum. Intolerance of uncertainty was found to be a significant mediator between sensory sensitivities and anxiety, as well as between anxiety and insistence on sameness behaviours. These results were not sensitive to age. Intolerance of uncertainty is an important factor to be considered in the conceptualisation and management of elevated rates of anxiety for adults on the autism spectrum.

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