Weight loss in chronic obstructive airways disease (COPD) is associated with an increased energy cost of breathing. To determine an association between body composition and the inflammatory response we studied 80 clinically stable patients. Body composition was determined anthropometrically and skeletal muscle mass was determined as the creatinine-height index (CHI). Forty patients had their nitrogen balance determined. Circulating concentrations of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and their soluble receptors were determined for 68 patients. Body mass index (BMI) was normal (> 20 kg/m(2)) in 55 patients, of whom 17 (31%) had a low CHI (< 80% predicted). A reduced CHI was associated with increased circulating levels of IL-6 (p = 0.001), TNF-alpha (p = 0.032) and their soluble receptors IL-6sr (p = 0.002), TNF-alpha sr1 (p = 0.03), and TNF-alpha sr2 (p = 0.001). Patients with a normal BMI and low CHI had inflammatory mediator levels similar to patients with a low BMI and CHI; both were significantly greater than in those with a normal BMI and CHI. Nitrogen balance was similar between normal and low CHI groups, although nitrogen excretion was significantly increased in the low CHI group. Skeletal muscle loss in COPD is probably multifactorial in origin, but our data suggest a link with systemic inflammation, even when weight loss is inapparent.

Intolerance to certain foods can cause a range of gut and systemic symptoms. The possibility that these can be caused by lactose has been missed because of “hidden” lactose added to many foods and drinks inadequately labelled, confusing diagnosis based on dietary removal of dairy foods. Two polymorphisms, C/T13910 and G/A22018, linked to hypolactasia, correlate with breath hydrogen and symptoms after lactose. This, with a 48 hour record of gut and systemic symptoms and a six hour breath hydrogen test, provides a new approach to the clinical management of lactose intolerance. The key is the prolonged effect of dietary removal of lactose. Patients diagnosed as lactose intolerant must be advised of “risk” foods, inadequately labelled, including processed meats, bread, cake mixes, soft drinks, and lagers. This review highlights the wide range of systemic symptoms caused by lactose intolerance. This has important implications for the management of irritable bowel syndrome, and for doctors of many specialties.

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