The recommendation is strong because the intervention is cheap, and has many positive effects on intermediary outcomes that are strongly associated with the reduction of adverse cardiovascular events and death. The benefits of lifestyle interventions clearly outweight harms.
A systematic review and meta-analysis «Dunkley AJ, Charles K, Gray LJ et al. Effectiveness of interventions for reducing diabetes and cardiovascular disease risk in people with metabolic syndrome: systematic review and mixed treatment comp»1 included 13 studies with a total of 3 907 subjects. Interventions for reversing metabolic syndrome or preventing development of type 2 diabetes and cardiovascular disease, alone or in combination, included lifestyle (diet and/or exercise) and pharmacological therapy. Both lifestyle (OR 3.81, 95% CI 2.47 to 5.88) and pharmacological interventions (OR 1.59, 95% CI 1.04 to 2.45) were superior compared with control for reversing metabolic syndrome.
Additional to the previous meta-analysis «Guzmán A, Navarro E, Obando L et al. Effectiveness of interventions for the reversal of a metabolic syndrome diagnosis: An update of a meta-analysis of mixed treatment comparison studies Biomedica 201»2, 2 other studies were included. Lifestyle interventions had 2.61 more chances to achieve the reversal of the metabolic syndrome than the control group.
A systematic review and meta-regression «van Namen M, Prendergast L, Peiris C. Supervised lifestyle intervention for people with metabolic syndrome improves outcomes and reduces individual risk factors of metabolic syndrome: A systematic rev»3 included 10 studies with a total of 1160 subjects. Compared to usual care, supervised lifestyle intervention demonstrated significant improvements in all but one of the components of metabolic syndrome: waist circumference (-4.9 cm, 95% CI -8.0 to -1.7), systolic blood pressure (-6.5 mmHg, 95% CI -10.7 to -2.3), diastolic blood pressure (-1.9 mmHg, 95% CI -3.6 to -0.2), triglycerides (SMD -0.46, 95% CI -0.88 to -0.04) and fasting glucose (SMD -0.68, 95% CI -1.20 to -0.15). Prevalence of metabolic syndrome was reduced by 39% in intervention group participants compared to control group participants (RR 0.61, 95% CI 0.38 to 0.96).
A systematic review with meta-analysis «Malakou E, Linardakis M, Armstrong MEG et al. The Combined Effect of Promoting the Mediterranean Diet and Physical Activity on Metabolic Risk Factors in Adults: A Systematic Review and Meta-Analysis o»4 included 11 studies (n = 1684). Compared to a control condition, mediterranean diet and physical activity reduced body weight (-3.68 kg, 95% CI -5.48 to -1.89), BMI (-0.64 kg/m², 95% CI -1.10 to -0.18), waist circumference (-1.62 cm, 95% CI -2.58 to -0.66), systolic (-0.83 mmHg, 95% CI -1.57 to -0.09) and diastolic blood pressure (-1.96 mmHg, 95% CI -2.57 to -1.35), blood glucose (-7.32 mg/dL, 95% CI -9.82 to -4.82), triglycerides (-18.47 mg/dL, 95% CI -20.13 to -16.80), total cholesterol (-6.30 mg/dL, 95% CI -9.59 to -3.02), and increased HDL-cholesterol (+3.99 mg/dL, 95% CI 1.22 to 6.77).
A systematic review and meta-analysis «Yamaoka K, Tango T. Effects of lifestyle modification on metabolic syndrome: a systematic review and meta-analysis. BMC Med 2012;10():138. »5 included 8 studies with total of 2 839 subjects. The relative proportion of patients with resolved metabolic syndrome in the lifestyle modification intervention group was approximately 2.0 (95% CI 1.5 to 2.7) times greater compared with the control group.