Environmental, medical, behavioural and disability factors associated with Helicobacter pylori infection in adults with intellectual disability.

In institutionalized adults with intellectual disability (ID), Helicobacter pylori infection occurs at approximately twice the rate it appears in the general population, and it may be responsible for the twofold higher rates of peptic ulcer disease and gastric cancer in this population. Medical, behavioural and additional environmental factors, as well as level of ID, may be related to the risk of infection with H. pylori. One hundred and sixty-eight adults with ID who were currently, had previously been or had never been institutionalized underwent a biopsychosocial evaluation. This included assessment of: level of ID using the Adaptive Behaviour Scale (ABS) Part I; levels of maladaptive behaviour using the ABS Part II; demographic, medical and environmental factors; as well as H. pylori tests using serology and faecal antigen. The overall rates of past or current infection with H. pylori in institutionalized and previously institutionalized participants were about twice that of the overall group of never-institutionalized participants, i.e. 87% and 79% compared to 44%, respectively (P < 0.001). The rates of H. pylori infection appeared to increase with age in the never-institutionalized group, but were consistently high across all ages in the other groups. The rate of infection was higher in those institutionalized for more than 5 years (95% versus 76%, P=0.02), in those with flatmates with excessive oral secretions (65% versus 21%, P < 0.001) or faecal incontinence (67% versus 27%, P < 0.001), and in those with more chronic illness and medications. All mean domain scores of the ABS Part I (Intellectual Disability) were significantly lower (indicating more severe ID) in the group currently infected with H. pylori compared to their non-infected counterparts. The majority of mean domain scores of the ABS Part II (Behaviour) were also worse, with half of these score differences reaching statistical significance in the currently infected group. The presence of alarm symptoms (e.g. vomiting, weight loss, haematemesis and melena), iron deficiency and body mass index were not significantly different in currently infected subjects. Adults with ID appear to be particularly at risk of infection with H. pylori. Environmental associations with infection include past or current institutionalization, a longer period of institutionalization, living with flatmates with excessive oral secretions and faecal incontinence. Medical associations include chronic disease and more medications, but not alarm symptoms or body mass index. Demographic associations may include increasing age in never-institutionalized adults, but no age effect in currently or previously institutionalized individuals. Psychosocial associations include more severe ID and maladaptive behaviour with current infection.