The prevalence of overweight and obesity is increasing worldwide.1 A comparison of data from 1976–802 with that from 1999–2000 shows that the prevalence of overweight (defined as body mass index, BMI, of 25–29.9 kg/m2) increased from 46% to 64.5%, and the prevalence of obesity (BMI ⩾ 30 kg/m2) doubled to 30.5%. The epidemic of obesity is not just isolated to the US, but is worldwide,3,,4 including less affluent countries.4

Obesity and overweight have many causes, including genetic, metabolic, behavioural and environmental. The rapid increase in prevalence suggests that behavioural and environmental influences predominate, rather than biological changes.

We summarize data from many studies evaluating the impact of obesity on mortality and morbidity, discuss some controversies and provide practical guidelines for managing obese patients.

Direct associations between obesity and several diseases, including diabetes mellitus, hypertension, dyslipidaemia and ischaemic heart disease, are well recognized. Despite this, the relationship between body weight and all-cause mortality is more controversial. A very high degree of obesity (BMI ⩾35 kg/m2) seems to be linked to higher mortality rates,5 but the relationship between more modest degrees of overweight and mortality is unclear.

Initial data from actuarial studies of more than 4 million men and women showed a direct positive association between body weight and overall mortality rates.6 Subsequent studies confirmed increased mortality risk above a certain threshold, but found a U-shaped association between weight and mortality.7,,8 In the Build study,9 there was a higher mortality in lean subjects, but there was no adjustment for smoking. The American Cancer Society found a much stronger association between leanness and mortality, specifically cancer mortality, in the group of smokers compared to non-smokers.10

The Harvard Alumni Study11 was a prospective cohort study of more than 19 000 middle-aged … 

Address correspondence to Dr S.D.H. Malnick, Department of Internal Medicine C, Kaplan Medical Centre, Rehovot 76100, Israel. email: stevash{at}trendline.co.il

https://www.bewegenismedicijn.nl/files/downloads/Malnick%20and%20Knobler,%202006.pdf

The medical complications of obesity

https://www.gastrojournal.org/article/S0016-5085(07)00583-5/pdf

Bariatric surgery: a review of procedures and outcomes.

Background
Risk factors for gallstone formation in the general population have been well studied while those after weight reduction surgery are unknown. The aim of this study was to identify the risk factors for the development of symptomatic gallstones after bariatric surgery.

/pdf/predictors-of-gallstone-formation-after-bariatric-surgery-a-4l0qn07du8.pdf

Predictors of gallstone formation after bariatric surgery: a multivariate analysis of risk factors comparing gastric bypass, gastric banding, and sleeve gastrectomy

Background: Routine cholecystectomy is often performed at the time of gastric bypass for morbid obesity. The aim of our study was to determine the incidence of gallstone formation requiring cholecystectomy following a laparoscopic Roux-en-Y gastric bypass (LRYGBP). Methods: 289 LRYGBP were performed between November 1999 and May 2002. 60 patients (21%) who had prior cholecystectomy were excluded. If gallstones were identified by intra-operative ultrasound (IOUS), simultaneous cholecystectomy was performed. Patients without gallstones were prescribed ursodiol for 6 months and scheduled for follow-up with transabdominal ultrasound. Results: During LRYGBP, gallstones were detected in 40 patients using IOUS (14%) and simultaneous cholecystectomy was performed. Of 189 patients with no stones identified by IOUS, 151 patients (80%) had a postoperative ultrasound after 6 months. 39 patients developed gallstones (22%) and 12 developed sludge (8%), as demonstrated by ultrasound at the time of follow-up. 11 patients had gallstone-related symptoms and subsequently underwent cholecystectomy (7%). 106 patients (70%) were gallstone-free at the time of ultrasound follow-up. Ursodiol compliance was found to be significantly lower for patients developing stones than for gallstone-free patients (38.9% vs 58.3%, z =-2.00, P = 0.045). Conclusions: There is a low incidence of symptomatic gallstones requiring cholecystectomy after LRYGBP. Prophylactic ursodiol is protective. Routine IOUS and selective cholecystectomy with close patient follow-up is a rational approach in the era of laparoscopy.

Is Routine Cholecystectomy Required During Laparoscopic Gastric Bypass

While LRYGB has become a cornerstone in the surgical treatment of morbidly obese patients, concomitant cholecystectomy during LRYGB remains a matter of debate. The aim of this meta-analysis was to estimate the rate and morbidity of subsequent cholecystectomy after laparoscopic Roux-en-Y gastric bypass (LRYGB) in obese patients. A meta-analysis was performed analyzing the rate and morbidity of subsequent cholecystectomy in patients who underwent LRYGB without concomitant cholecystectomy. Thirteen studies met the inclusion criteria. The rate of subsequent cholecystectomy was 6.8 % (95 % CI, 5.0-8.7 %) based on 6,048 obese patients who underwent LRYGB without concomitant cholecystectomy. The rate of subsequent cholecystectomy due to biliary colic or gallbladder dyskinesia was 5.3 %; due to cholecystitis, 1.0 %; choledocholithiasis, 0.2 %; and biliary pancreatitis, 0.2 %. The mortality after subsequent cholecystectomy was 0 % (95 % CI, 0-0.1 %). The surgery-related complication rate after subsequent cholecystectomy was 1.8 % (95 % CI, 0.7-3.4 %) resulting in a risk of 0.1 % (95 % CI, 0.03-0.3 %) to suffer from a cholecystectomy-related complication in patients undergoing LRYGB without concomitant cholecystectomy. A prophylactic concomitant cholecystectomy during LRYGB should be avoided in patients without cholelithiasis and exclusively be performed in patients with symptomatic biliary disease.

Concomitant Cholecystectomy During Laparoscopic Roux-en-Y Gastric Bypass in Obese Patients Is Not Justified: A Meta-Analysis

Background: Obesity alone and rapid weight loss induced by bariatric surgery are recognized risk factors for the development of cholelithiasis. The decision to perform prophylactic cholecystectomy at the time of bariatric operations remains controversial and at the surgeon's discretion. Methods: From June 1998 to April 2001, 103 patients underwent Roux-en-Y gastric bypass (RYGBP) in Hospital das Clinicas/Unicamp (SP). 88 of these 103 patients had their preoperative ultrasonography of gallbladder recovered. 19 of these 88 patients showed gallstones before RYGBP, and the remaining 69 did not have ultrasonographic evidence of cholelithiasis. 36 of these 69 patients were followed with ultrasonography during the 12 postoperative months. They were divided into 2 groups: those who formed gallstones (n=19) and those who did not (n=17), to evaluate the importance of sex, age, preoperative BMI, preoperative excess weight and postoperative percent excess weight loss as risk factors in the gallstone formation. Results: Preoperative incidence of cholelithiasis in the 88 operated patients was 21.6% and postoperative incidence in the 36 patients followed by ultrasonograph was 52.8%. There was no statistical evidence that postoperative gallstone formation is associated significantly with the variables studied. Conclusion: This study confirms the high correlation between morbid obesity, rapid weight loss and gallbladder disease. Predictive risk factors for gallstone formation were not found.

Carlos Iglezias Brandão de Oliveira

Papers

Impact of rapid weight reduction on risk of cholelithiasis after bariatric surgery.