"The study findings are that autistic people on average have lower QoL [quality of life] than the general population in the UK." Further: "Three main characteristics were predictive of lower QoL in almost all domains: being female, having a current mental health diagnosis and higher severity of autism symptoms." By contrast: "Significant positive predictors of QoL were: being employed (physical QoL), receiving support (social and environment QoL), and being in a relationship (social QoL)."
So said the findings reported by David Mason and colleagues  describing the results of a study that examined "quality of life (QoL) of a large sample of autistic adults in the UK and investigates characteristics that may be predictive of QoL." This is a vitally important topic because perceived quality of life IS important and has been discussed before in the peer-reviewed research arena with autism in mind (see here).
This time around the focus was on 'self-reported' quality of life for autistic adults who submitted data as part of a research initiative "into the life experiences of autistic adults, the Adult Autism Spectrum Cohort‐UK." Some 370 people (mostly) formally diagnosed with an autism spectrum disorder (ASD) completed the WHOQoL‐BREF, a quality of life assessment schedule developed by the World Health Organisation, as well as the Social Responsiveness Scale (SRS) and a initiative-specific questionnaire that collected various information including that about "everyday life including relationship status; home life including living alone or with family members (family of origin or spouse/partner); employment including paid employment, volunteering, or retired; education including type of school and qualifications achieved; support including who supports the adult and how often support is needed; mental health/neurological conditions including current diagnoses and type of medication/therapy; physical health conditions; and autism spectrum in other family members." Acquired data was put into the statistical 'measuring' machine and trends were reported.
So, a large proportion of participants were aged between 41 and 60 years old (~40%). The sex/gender ratios were fairly evenly split (males: 54% vs. females: 43% vs. 'prefer not to say' ~3%). The vast majority of respondents reported either a mental health issue as being concurrent to their autism diagnosis/status (~70%) or a physical health issue as being present (70%). I don't think we were actually told all the specific diagnostic categories that were included under 'a mental health issue' or 'a physical health issue' but some clues are provided in the text: "most commonly depression and/or anxiety" and "sleep problems, or hypertension." The WHOQoL‐BREF, by the way, provides information on QoL in various domains: physical, psychological, social and environment. Authors therefore report that: "Reported QoL for autistic adults was lower across all four domains than UK norms."
Then to those potential predictors of 'poorer' or 'better' quality of life, as some further statistical analysis was actioned on the collected data. Quite consistently - in the physical, psychological and environment domains - the same three elements cropped up as potentially predicting poorer quality of life: being female, having a comorbid mental health diagnosis and total scores on the SRS (an instrument that "measures autism characteristics" with a focus on social aspects). Looking at the statistical strength of the various factors observed, I'd have to say that the SRS score (total) - that measure of 'autism characteristics' - was the one that seemed to be most strongly related to QoL. Yes, the implications are that the [social] manifestation of autism itself *could* be an important driver of poorer QoL. Insofar as the factors potentially related to a more positive (better) quality of life, being employed, receiving support and being in a relationship were all mentioned, but certainly not as consistently across all the various WHOQoL‐BREF domains as noted in those negative predictors.
The authors highlight a few positives and negatives in relation to their study: use of a "robust measure of QoL is a strength", pretty large sample size and the collection of some good quality 'complete' results. That being said, they also note that a general QoL questionnaire might not gather all the important information relevant to QoL in the context of autism (I do wonder if all that ICF core sets of autism work might help matters on future research occasions). And then there's the issue of representativeness to consider, when it comes to the applicability of Mason results to the (very) wide autism spectrum (see here)...
Recommendations - 'implications' - aplenty spring from the Mason results. Focus in on better screening and treatment/management of mental health (and physical health) issues when concurrent to an autism diagnosis (see here and see here for examples). Make employment - long-term employment - work better for those on the autism spectrum (see here). Devote greater resources to discovering what factors surrounding female autism might lead to poorer quality of life. All noble sentiments worth pursuing. Alongside, are those results about autism severity also seemingly impacting on QoL. Does this perhaps also imply that moves to 'intervene' on core autistic symptoms might also be a target too? Y'know, on the understanding that 'core autism features' have also been *correlated* to some other, rather extreme endpoints also significantly affecting quality of life (see here)?
Addition: 10 May 2018. Y'know I mentioned that SRS scores - "measures autism characteristics" - might be an important variable when it comes to quality of life? Well, it seems another cohort came to similar conclusions  (click here for a larger view of figure b and those self SRS scores)...
 Mason D. et al. Predictors of quality of life for autistic adults. Autism Res. 2018. May 7.
 Oakley B. et al. Why Is Quality of Life Reduced in Individuals with Autism Spectrum Conditions? Investigating the Impact of Core Symptoms and Psychiatric Comorbidities on Quality of Life in the EU-AIMS LEAP Cohort. INSAR 2018.