Small bowel bacterial overgrowth is not seen in healthy adults but is in disabled older adults.

Background/aims: Small bowel bacterial overgrowth (SBBO) is defined as an abnormal increase in the number of bacteria in the small intestine, and may be occult in older adults. The aim of this study was to determine whether small bowel bacterial overgrowth (SBBO) is found in healthy older people as a concomitant of normal aging or is seen only in disabled or frail older people, excluding patients with intestinal disease and those who had undergone upper intestinal or gastric surgery.

Methodology: Forty-one relatively healthy older people, aged 74.6 +/- 1.7 (mean +/- SE) years, who engage in regular exercise, and 42 variously disabled older people, average age 78.8 +/- 1.1 years, who commute to a day-care center participated in this study. SBBO was determined by a breath hydrogen (H2) test after ingestion of 50g of glucose solution dissolved in 200mL of water. Physical activity was judged from the number of steps walked per day as measured by a pedometer. Food intake was assessed by an interview.

Results: No SBBO-positive subject was seen among the healthy, while 11 (25.6%) of the disabled older adults were positive. The number of steps/day taken by the disabled subjects was extremely low, only 22.3% of that of the healthy (P<0.001). No significant difference was seen between the groups in food intake. The mean age of the SBBO-positive patients was relatively high, 81.5 +/- 2.2 years, and 5 (45.4%) of them were underweight, with a BMI<18.5.

Conclusions: Our results and previous studies indicate that SBBO is seen only in patients with intestinal disease and disabled or frail older people.