Assessment of people who may be underweight
A multidisciplinary approach is often needed to assess a person with developmental disability suspected of being underweight; assessment includes anthropometry (eg body mass index [BMI] and skin folds) and identifying the cause and associated problems. Consider the concerns and priorities of the person with developmental disability, and those of their family or carers.
Measure the person’s height and weight to calculate BMI (or percentile, for children):
- for adults, see Body mass index to assess body weight for classification of underweight according to BMI
- for children, see growth percentile charts.
Serial weight measurements are useful to assess bodyweight and monitor efficacy of interventions. For people who are non-ambulant or have poor balance, obtaining an accurate weight is difficult. Specialised wheelchair or hoist scales may be available through local hospital outpatient departments or community health centres—consult hospital dietitians for advice on availability. When height or weight cannot be accurately measured, triceps skin fold thickness (ie measurement of subcutaneous fat) or mid-upper arm circumference measurements can be used.
Causes of being underweight include:
- dysphagia
- enteral nutrition (eg percutaneous endoscopic gastrostomy [PEG] feeding) when nutrition is suboptimal
- malabsorption disorder (eg coeliac disease)
- reduced food intake (eg limited availability of feeding support, food selectivity, neglect)
- increased energy requirements (eg those with agitation, restlessness, hyperactivity)
- poor oral health
- malignancy
- depression
- diabetes
- thyroid disorder.
Food selectivity may reflect taste and texture preferences, including cultural and social factors that are not being addressed at mealtimes. Food selectivity is common in people with autism spectrum disorder. The general practitioner should ask about food selectivity in people who are underweight.
Look for complications associated with being underweight (eg aspiration, dehydration, gastro-oesophageal reflux disease [GORD], constipation, anaemia, specific micronutrient deficiencies, acute or chronic infection due to reduced immunity).
Refer people with developmental disability who are chronically underweight for further assessment—eg gastroenterologist, dietitian for dietary analysis (including food preferences, sensitivities), speech pathologist for swallowing and functional assessment. See also Facilitating a multidisciplinary approach to care.