Abstract
Objective
To assess if weight loss interventions for adults with obesity affect all-cause, cardiovascular and cancer mortality, cardiovascular disease, cancer, and body weight.
Design
Systematic review and meta-analysis of randomised controlled trials (RCTs) using random effects, estimating risk ratios (RRs) and mean differences (MDs). Heterogeneity investigated using Cochran’s Q and I2 statistics. Quality of evidence assessed by GRADE criteria.
Data sources
We searched Medline, Embase, the Cochrane Central Register of Controlled Trials, and full texts in our trials’ registry for data not evident in databases. We contacted authors for unpublished data.
Eligibility criteria for selecting studies
RCTs of dietary interventions targeting weight loss, with or without exercise advice or programmes, for adults with obesity and follow-up ≥ 1 year.
Results
We included 54 RCTs with 30,206 participants. All but one trial evaluated low-fat reducing diets. For the primary outcome, there was high quality evidence that weight loss interventions decrease all-cause mortality (34 trials, 685 events; RR 0.82, 95% CI (Confidence Interval): 0.71 to 0.95), 6 fewer deaths per 1000 participants (95% CI 2 fewer to 10 fewer). For other primary outcomes there was moderate quality evidence for an effect on cardiovascular mortality (8 trials, 134 events; RR 0.93, 95% CI: 0.67 to 1.31) and very low quality evidence for an effect on cancer mortality (8 trials, 34 events; RR 0.58, 95% CI 0.30 to 1.11).
Twenty four trials (15,176 participants) reported high quality evidence on participants developing new cardiovascular events (1043 events; RR 0.93, 95% CI 0.83 to 1.04).
Nineteen trials (6330 participants) provided very low quality evidence on participants developing new cancers (103 events; RR 0.92, 95% CI 0.63 to 1.36).
Conclusions
Weight reducing diets, usually low in fat and saturated fat, with or without exercise advice or programmes, may reduce premature all-cause mortality in adults with obesity.
To assess if weight loss interventions for adults with obesity affect all-cause, cardiovascular and cancer mortality, cardiovascular disease, cancer, and body weight.
Design
Systematic review and meta-analysis of randomised controlled trials (RCTs) using random effects, estimating risk ratios (RRs) and mean differences (MDs). Heterogeneity investigated using Cochran’s Q and I2 statistics. Quality of evidence assessed by GRADE criteria.
Data sources
We searched Medline, Embase, the Cochrane Central Register of Controlled Trials, and full texts in our trials’ registry for data not evident in databases. We contacted authors for unpublished data.
Eligibility criteria for selecting studies
RCTs of dietary interventions targeting weight loss, with or without exercise advice or programmes, for adults with obesity and follow-up ≥ 1 year.
Results
We included 54 RCTs with 30,206 participants. All but one trial evaluated low-fat reducing diets. For the primary outcome, there was high quality evidence that weight loss interventions decrease all-cause mortality (34 trials, 685 events; RR 0.82, 95% CI (Confidence Interval): 0.71 to 0.95), 6 fewer deaths per 1000 participants (95% CI 2 fewer to 10 fewer). For other primary outcomes there was moderate quality evidence for an effect on cardiovascular mortality (8 trials, 134 events; RR 0.93, 95% CI: 0.67 to 1.31) and very low quality evidence for an effect on cancer mortality (8 trials, 34 events; RR 0.58, 95% CI 0.30 to 1.11).
Twenty four trials (15,176 participants) reported high quality evidence on participants developing new cardiovascular events (1043 events; RR 0.93, 95% CI 0.83 to 1.04).
Nineteen trials (6330 participants) provided very low quality evidence on participants developing new cancers (103 events; RR 0.92, 95% CI 0.63 to 1.36).
Conclusions
Weight reducing diets, usually low in fat and saturated fat, with or without exercise advice or programmes, may reduce premature all-cause mortality in adults with obesity.
| Original language | English |
|---|---|
| Article number | j4849 |
| Journal | BMJ |
| Volume | 359 |
| DOIs | |
| Publication status | Published - 14 Nov 2017 |
Keywords
- obesity
- weight reduction
- reducing diet
- mortality
- cardiovascular disease
- cancer
- systematic review
- randomised controlled trials
Access to Document
- Effects of weight loss interventions for adults who are obese
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Fingerprint
Dive into the research topics of 'Effects of weight loss interventions for adults who are obese on mortality, cardiovascular disease and cancer: a systematic review and meta-analysis'. Together they form a unique fingerprint.Profiles
-
Alison Avenell
- School of Medicine, Medical Sciences & Nutrition, Health Services Research Unit (HSRU) - Clinical Chair in Health Services Research
- Institute of Applied Health Sciences
Person: Clinical Academic
-
Jemma Hudson
- School of Medicine, Medical Sciences & Nutrition, Health Services Research Unit (HSRU) - Research Fellow
Person: Academic Related - Research
-
Graeme MacLennan
- School of Medicine, Medical Sciences & Nutrition, Health Services Research Unit (HSRU) - Director (CHaRT)
- Institute of Applied Health Sciences
Person: Academic, Academic Related - Research