Bone Health and Nutrient Intake 2 to 5 years after Biliopancreatic Diversion with Duodenal Switch : Master Thesis in Clinical Nutrition

Abstract

This report describes findings from anthropometric, bone mineral density, biochemical and dietary assessments in relation to bone health during follow-up consultations of biliopancreatic bypass with duodenal switch (BPD-DS) patients followed at the Department of Preventive Cardiology, Ullevål University Hospital from November 2006 to May 2007. The study population consisted of 65 BPD-DS patients, 55 women and 10 men, who had undergone surgery 2-5 years earlier. All patients had achieved satisfactory weight loss at the time of follow-up assessments. The study population had a mean weight loss of 62 kg, and an average of 76 % of excess weight was lost. Analyses showed a high incidence of increased bone turnover and fat soluble vitamin deficiency (vitamin A and D) after BPD-DS. Average bone mineral density (BMD) was within normal range, but 25-32 % had decreased levels (less than -1.0 SD of reference population) and men had significantly lower BMD than women. Patients with low BMD tended to be older, have lower BMI pre-surgery and lost less weight after the surgery. Reductions in BMI had the strongest correlation to BMD. Biochemical markers of bone turnover were increased in a large proportion with serum-PTH levels increased in 92 % and serum-I-CTP increased in 45 % of cases. We found that a greater reduction in BMI was associated with higher levels of the bone resorption marker I-CTP, which indicated that the high rate of weight loss post-surgery increases bone turnover. We found no relationship between nutrient intake and nutrient status or BMD. Several factors may have affected these findings. Most importantly, we only obtained dietary registration from 45 % of the study population. No relationship was detected between supplement compliance and nutrient status or BMD. This could indicate that absorption of supplement derived nutrients may be even poorer than initially anticipated. Nutritional monitoring over a longer time period, and for several years post-surgery, may be necessary to detect any relationship between such parameters. Our data is not sufficient to accept the H0 hypothesis which states that nutrient intake after BPD-DS is not associated with bone health. Further studies are needed to elucidate this, and we continue to emphasize the importance of ensuring patient compliance to post-surgery nutritional recommendations and follow-up procedures.