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Lars Sjöström,
Markku Peltonen,
Peter Jacobson,
C David Sjöström,
Kristjan Karason,
Hans Wedel,
Sofie Ahlin,
Åsa Anveden,
Calle Bengtsson,
Gerd Bergmark, [......],
Björn Carlsson, Sven Dahlgren,
Jan Karlsson,
Anna-Karin Lindroos,
Hans Lönroth,
Kristina Narbro,
Ingmar Näslund,
Torsten Olbers,
Per-Arne Svensson,
Lena M S Carlsson
[show abstract]
[hide abstract]
ABSTRACT: Obesity is a risk factor for cardiovascular events. Weight loss might protect against cardiovascular events, but solid evidence is lacking.
To study the association between bariatric surgery, weight loss, and cardiovascular events.
The Swedish Obese Subjects (SOS) study is an ongoing, nonrandomized, prospective, controlled study conducted at 25 public surgical departments and 480 primary health care centers in Sweden of 2010 obese participants who underwent bariatric surgery and 2037 contemporaneously matched obese controls who received usual care. Patients were recruited between September 1, 1987, and January 31, 2001. Date of analysis was December 31, 2009, with median follow-up of 14.7 years (range, 0-20 years). Inclusion criteria were age 37 to 60 years and a body mass index of at least 34 in men and at least 38 in women. Exclusion criteria were identical in surgery and control patients. Surgery patients underwent gastric bypass (13.2%), banding (18.7%), or vertical banded gastroplasty (68.1%), and controls received usual care in the Swedish primary health care system. Physical and biochemical examinations and database cross-checks were undertaken at preplanned intervals.
The primary end point of the SOS study (total mortality) was published in 2007. Myocardial infarction and stroke were predefined secondary end points, considered separately and combined.
Bariatric surgery was associated with a reduced number of cardiovascular deaths (28 events among 2010 patients in the surgery group vs 49 events among 2037 patients in the control group; adjusted hazard ratio [HR], 0.47; 95% CI, 0.29-0.76; P = .002). The number of total first time (fatal or nonfatal) cardiovascular events (myocardial infarction or stroke, whichever came first) was lower in the surgery group (199 events among 2010 patients) than in the control group (234 events among 2037 patients; adjusted HR, 0.67; 95% CI, 0.54-0.83; P < .001).
Compared with usual care, bariatric surgery was associated with reduced number of cardiovascular deaths and lower incidence of cardiovascular events in obese adults.
JAMA The Journal of the American Medical Association 01/2012; 307(1):56-65. · 30.03 Impact Factor
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Lars Sjöström,
Anders Gummesson,
C David Sjöström,
Kristina Narbro,
Markku Peltonen,
Hans Wedel,
Calle Bengtsson,
Claude Bouchard,
Björn Carlsson, Sven Dahlgren, [......],
Kristjan Karason,
Jan Karlsson,
Bo Larsson,
Anna-Karin Lindroos,
Hans Lönroth,
Ingmar Näslund,
Torsten Olbers,
Kaj Stenlöf,
Jarl Torgerson,
Lena M S Carlsson
[show abstract]
[hide abstract]
ABSTRACT: Obesity is a risk factor for cancer. Intentional weight loss in the obese might protect against malignancy, but evidence is limited. To our knowledge, the Swedish Obese Subjects (SOS) study is the first intervention trial in the obese population to provide prospective, controlled cancer-incidence data.
The SOS study started in 1987 and involved 2010 obese patients (body-mass index [BMI] >or=34 kg/m(2) in men, and >or=38 kg/m(2) in women) who underwent bariatric surgery and 2037 contemporaneously matched obese controls, who received conventional treatment. While the main endpoint of SOS was overall mortality, the main outcome of this exploratory report was cancer incidence until Dec 31, 2005. Cancer follow-up rate was 99.9% and the median follow-up time was 10.9 years (range 0-18.1 years).
Bariatric surgery resulted in a sustained mean weight reduction of 19.9 kg (SD 15.6 kg) over 10 years, whereas the mean weight change in controls was a gain of 1.3 kg (SD 13.7 kg). The number of first-time cancers after inclusion was lower in the surgery group (n=117) than in the control group (n=169; HR 0.67, 95% CI 0.53-0.85, p=0.0009). The sex-treatment interaction p value was 0.054. In women, the number of first-time cancers after inclusion was lower in the surgery group (n=79) than in the control group (n=130; HR 0.58, 0.44-0.77; p=0.0001), whereas there was no effect of surgery in men (38 in the surgery group vs 39 in the control group; HR 0.97, 0.62-1.52; p=0.90). Similar results were obtained after exclusion of all cancer cases during the first 3 years of the intervention.
Bariatric surgery was associated with reduced cancer incidence in obese women but not in obese men.
Swedish Research Council, Swedish Foundation for Strategic Research, Swedish Federal Government under the LUA/ALF agreement, Hoffmann La Roche, Cederoths, AstraZeneca, Sanofi-Aventis, Ethicon Endosurgery.
The lancet oncology 06/2009; 10(7):653-62. · 14.47 Impact Factor
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Lars Sjöström,
Kristina Narbro,
C David Sjöström,
Kristjan Karason,
Bo Larsson,
Hans Wedel,
Ted Lystig,
Marianne Sullivan,
Claude Bouchard,
Björn Carlsson, [......],
Peter Jacobson,
Jan Karlsson,
Anna-Karin Lindroos,
Hans Lönroth,
Ingmar Näslund,
Torsten Olbers,
Kaj Stenlöf,
Jarl Torgerson,
Göran Agren,
Lena M S Carlsson
[show abstract]
[hide abstract]
ABSTRACT: Obesity is associated with increased mortality. Weight loss improves cardiovascular risk factors, but no prospective interventional studies have reported whether weight loss decreases overall mortality. In fact, many observational studies suggest that weight reduction is associated with increased mortality.
The prospective, controlled Swedish Obese Subjects study involved 4047 obese subjects. Of these subjects, 2010 underwent bariatric surgery (surgery group) and 2037 received conventional treatment (matched control group). We report on overall mortality during an average of 10.9 years of follow-up. At the time of the analysis (November 1, 2005), vital status was known for all but three subjects (follow-up rate, 99.9%).
The average weight change in control subjects was less than +/-2% during the period of up to 15 years during which weights were recorded. Maximum weight losses in the surgical subgroups were observed after 1 to 2 years: gastric bypass, 32%; vertical-banded gastroplasty, 25%; and banding, 20%. After 10 years, the weight losses from baseline were stabilized at 25%, 16%, and 14%, respectively. There were 129 deaths in the control group and 101 deaths in the surgery group. The unadjusted overall hazard ratio was 0.76 in the surgery group (P=0.04), as compared with the control group, and the hazard ratio adjusted for sex, age, and risk factors was 0.71 (P=0.01). The most common causes of death were myocardial infarction (control group, 25 subjects; surgery group, 13 subjects) and cancer (control group, 47; surgery group, 29).
Bariatric surgery for severe obesity is associated with long-term weight loss and decreased overall mortality.
New England Journal of Medicine 09/2007; 357(8):741-52. · 53.30 Impact Factor
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Lars Sjöström,
Anna-Karin Lindroos,
Markku Peltonen,
Jarl Torgerson,
Claude Bouchard,
Björn Carlsson, Sven Dahlgren,
Bo Larsson,
Kristina Narbro,
Carl David Sjöström,
Marianne Sullivan,
Hans Wedel
[show abstract]
[hide abstract]
ABSTRACT: Weight loss is associated with short-term amelioration and prevention of metabolic and cardiovascular risk, but whether these benefits persist over time is unknown.
The prospective, controlled Swedish Obese Subjects Study involved obese subjects who underwent gastric surgery and contemporaneously matched, conventionally treated obese control subjects. We now report follow-up data for subjects (mean age, 48 years; mean body-mass index, 41) who had been enrolled for at least 2 years (4047 subjects) or 10 years (1703 subjects) before the analysis (January 1, 2004). The follow-up rate for laboratory examinations was 86.6 percent at 2 years and 74.5 percent at 10 years.
After two years, the weight had increased by 0.1 percent in the control group and had decreased by 23.4 percent in the surgery group (P<0.001). After 10 years, the weight had increased by 1.6 percent and decreased by 16.1 percent, respectively (P<0.001). Energy intake was lower and the proportion of physically active subjects higher in the surgery group than in the control group throughout the observation period. Two- and 10-year rates of recovery from diabetes, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, hypertension, and hyperuricemia were more favorable in the surgery group than in the control group, whereas recovery from hypercholesterolemia did not differ between the groups. The surgery group had lower 2- and 10-year incidence rates of diabetes, hypertriglyceridemia, and hyperuricemia than the control group; differences between the groups in the incidence of hypercholesterolemia and hypertension were undetectable.
As compared with conventional therapy, bariatric surgery appears to be a viable option for the treatment of severe obesity, resulting in long-term weight loss, improved lifestyle, and, except for hypercholesterolemia, amelioration in risk factors that were elevated at baseline.
New England Journal of Medicine 01/2005; 351(26):2683-93. · 53.30 Impact Factor
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Lars Sjöström,
Markku Peltonen,
Peter Jacobson,
C. David Sjöström,
Kristjan Karason,
Hans Wedel,
Sofie Ahlin,
Åsa Anveden,
Calle Bengtsson,
Gerd Bergmark, [......],
Björn Carlsson, Sven Dahlgren,
Jan Karlsson,
Anna-Karin Lindroos,
Hans Lönroth,
Kristina Narbro,
Ingmar Näslund,
Torsten Olbers,
Per-Arne Svensson,
Lena M. S. Carlsson
[show abstract]
[hide abstract]
ABSTRACT: Context
Obesity is a risk factor for cardiovascular events. Weight loss might protect against cardiovascular events, but solid evidence is lacking.Objective
To study the association between bariatric surgery, weight loss, and cardiovascular events.Design, Setting, and Participants
The Swedish Obese Subjects (SOS) study is an ongoing, nonrandomized, prospective, controlled study conducted at 25 public surgical departments and 480 primary health care centers in Sweden of 2010 obese participants who underwent bariatric surgery and 2037 contemporaneously matched obese controls who received usual care. Patients were recruited between September 1, 1987, and January 31, 2001. Date of analysis was December 31, 2009, with median follow-up of 14.7 years (range, 0-20 years). Inclusion criteria were age 37 to 60 years and a body mass index of at least 34 in men and at least 38 in women. Exclusion criteria were identical in surgery and control patients. Surgery patients underwent gastric bypass (13.2%), banding (18.7%), or vertical banded gastroplasty (68.1%), and controls received usual care in the Swedish primary health care system. Physical and biochemical examinations and database cross-checks were undertaken at preplanned intervals.Main Outcome Measures
The primary end point of the SOS study (total mortality) was published in 2007. Myocardial infarction and stroke were predefined secondary end points, considered separately and combined.Results
Bariatric surgery was associated with a reduced number of cardiovascular deaths (28 events among 2010 patients in the surgery group vs 49 events among 2037 patients in the control group; adjusted hazard ratio [HR], 0.47; 95% CI, 0.29-0.76; P = .002). The number of total first time (fatal or nonfatal) cardiovascular events (myocardial infarction or stroke, whichever came first) was lower in the surgery group (199 events among 2010 patients) than in the control group (234 events among 2037 patients; adjusted HR, 0.67; 95% CI, 0.54-0.83; P < .001).Conclusion
Compared with usual care, bariatric surgery was associated with reduced number of cardiovascular deaths and lower incidence of cardiovascular events in obese adults.
Figures in this Article
Most epidemiological studies have shown that obesity is associated with increased cardiovascular morbidity and mortality.1- 2 Weight loss improves diabetes and other intermediate risk factors for cardiovascular disease,3- 6 suggesting that weight loss could also reduce the incidence of cardiovascular events. However, weight loss has been paradoxically associated with an increased incidence of cardiovascular events in most epidemiological studies,7- 9 even in participants who were overweight or obese at baseline.10 Some observational studies suggest that self-reported intentional weight loss is associated with a decreased incidence of cardiovascular events.11 Other studies suggest the opposite.12- 13 Results of these studies might be confounded by inclusion of participants with unintentional weight loss.11- 13
Lifestyle interventions to prohibit diabetes14 have not prevented cardiovascular events, not even after 10 to 20 years of follow-up.15- 16 Similarly lifestyle interventions combined with antiobesity medications have either shown no effect on primary cardiovascular end points17 or an increased incidence of cardiovascular events in the drug treatment group.18 Taken together, nonsurgical weight loss trials in obese participants have failed to yield a benefit in terms of cardiovascular event rates.15- 18
Retrospective cohort studies of bariatric surgery demonstrated an association between bariatric surgery with a reduced incidence of cardiovascular events.19- 20 However, these studies were limited because of incomplete information about the participants causing uncontrolled, confounding conditions that might have influenced the results of these studies. To date, carefully controlled, prospective analyses on cardiovascular events in patients who have had bariatric surgery and matched obese participants have not been reported.
Two prospective, controlled, long-term studies examining the relationship between weight loss and cardiovascular outcomes are ongoing (Look AHEAD [Actions for HEAlth in Diabetes]21 and SOS [Swedish Obese Subjects]).5,22- 24 Look AHEAD's 4-year results on weight loss and risk factors were recently published,21 but the 12-year results of lifestyle intervention on cardiovascular events are not yet available in the 5145 participants.
The rationale for the nonrandomized, prospective, controlled SOS study was to fill the knowledge gap regarding the association between type of treatment (bariatric surgery vs usual care) and hard end points (primarily mortality). For ethical reasons related to the high postoperative mortality in the 1980s, a randomized design was not approved and a matched study was therefore undertaken.5,22- 24 We have previously reported that bariatric surgery is associated with reduced incidence of diabetes (median follow-up time, 2 years)5 and cancer (10.9 years)24 and with reduced overall mortality (10.9 years),23 the primary end point of the SOS study.
In this article, we test the hypothesis that bariatric surgery is associated with a reduced incidence of cardiovascular events. These were defined as a combination variable of fatal and nonfatal acute myocardial infarction (MI) and stroke, whichever came first. Myocardial infarction and stroke were also examined as separate end points. These secondary end points were predefined in 1987 in the original study protocol. Because current guidelines and position statements for selection of patients undergoing bariatric surgery25- 28 are based on expert opinions and not on treatment effects in prospective, controlled interventions, we have undertaken post hoc analyses to explore if baseline characteristics in the SOS study predict the surgical treatment benefit with respect to cardiovascular events. In addition, we have examined the relationship between weight change and the incidence of cardiovascular events.
JAMA The Journal of the American Medical Association 307(1):56-65. · 30.03 Impact Factor
