Effect of a Lifestyle Intervention Program With Energy-Restricted Mediterranean Diet and Exercise on Weight Loss and Cardiovascular Risk Factors: One-Year Results of the PREDIMED-Plus Trial

Literature - Salas-Salvadó J, Diaz-López A, Ruiz-Canela M et al. - Diabetes Care 2018: published online ahead of print

Introduction and methods

Moderate weight loss through lifestyle intervention (5-10% of initial body weight) is associated with improvement of cardiometabolic abnormalities in overweight/obese individuals [1,2] and reduction in risk of T2DM [3]. However, the long-term cardiovascular impact of weight loss has never been demonstrated in randomized clinical trials (RCTs).

This sub-analysis of the parallel-group, multicenter, randomized PREvención con DIeta MEDiterránea (PREDIMED)-Plus trial assessed the 12-month effects of an intensive lifestyle intervention on weight loss, adiposity markers, and intermediate markers of CV risk, including overweight/obese (BMI ≥27 and <40 kg/m²) individuals (aged 55-75 years) with metabolic syndrome (MetS) who were randomized 1:1 to receive either the intervention (intervention group [IG]; n=327) or usual care (control group [CG]; n=299). Subjects with a history of CVD were excluded, leaving a study sample of 626 participants.

The lifestyle intervention consisted of an energy restricted Mediterranean diet (erMedDiet), physical activity (PA) promotion, and behavioral support. Questionnaires were used to assess self-reported adherence to the erMedDiet, food frequency, and physical activity.

The primary endpoint was between-group differences in weight loss at 6 and 12 months of intervention. Weight-related secondary endpoints at 6 and 12 months were the between-group differences in the proportions of participants who had either a stable weight or weight below baseline values, those who lost at least 5% or 10% of their initial weight, and those reversing obesity (changing BMI from ≥30 to <30kg/m²).

Main results

Compliance with dietary and lifestyle interventions

• At 6 and 12 months, participants in the IG reported a significantly greater achievement in 10/17 items of the questionnaire of adherence to the erMedDiet, with a net increase of two points, compared to the CG at 12 months (3.7 vs. 1.6 points, P<0.001).
• The general food pattern improved significantly in both groups, but the consumption of total cereals and refined cereals improved more in the IG, compared to CG, after 12 months (-34.6 vs. -6.4, P<0.001 and -64.1 vs. -19.7, P<0.001, respectively).
• At 12 months, the IG showed more pronounced reductions in daily energy intake (P=0.05), compared to the CG, with a lower intake of carbohydrates (-4.6% vs. -1.9%, P<0.001) and higher intakes of protein (0.9% vs. -0.01%, P<0.001), total fat (3.6% vs. 2.1%, P=0.01), and monounsaturated fat (4.5% vs. 2.6%, P<0.001).
• In the IG, total leisure time PA was significantly increased at 12 months (361.5-108 METs.min/day), whereas this decreased in the CG (416.4-4.01 METs.min/day) (P=0.001). Proportions of participants meeting recommendations on PA increased in the IG (11.5%), whereas this decreased in CG (-0.7%) at 12 months (P=0.001).

Intention-to-treat analysis: Weight loss and maintenance

• At 6 and 12 months, mean weight losses differed significantly between the IG and CG (6 months: -2.4 [-2.7%] vs. -0.4 kg [-0.5%], P<0.001; 12 months -3.2 [-3.7%] vs. -0.7 kg [-0.8%], P<0.001), with a mean significant difference in weight changes between IG and CG of -2.5 kg (-3.1 to -1.9), which was consistent among subgroups.
• At 6 and 12 months, reductions in BMI were greater in the IG compared to the CG (6 months: -0.9 vs. -0.2 kg/m², P<0.001; 12 months -1.2 vs. -0.3 kg/m², P<0.001), which remained similar after multivariable adjustments.
• Compared to CG, more participants in the IG lost weight below their initial weight at 6 months (81.3% vs. 58.4%, P<0.001) and 12 months (84.1% vs. 57.9%, P<0.001).
• Compared to CG, significantly more participants in the IG attained weight loss of ≥5% (33.7% vs. 11.9%, P<0.001) and ≥10% (6.9% vs. 2.2%, P<0.001) at 12 months.
• Participants in the IG showed a greater reduction in waist circumference than those in the CG at 6 months (-3.0 vs. -0.9 cm, P<0.001) and 12 months (-3.1 vs. -0.7 cm, P<0.001).
• In the IG significant reductions in fasting glucose (-0.23 mmol/L), HbA1c (-1.25 mmol/mol [-0.12%]), insulin (-26.2 pmol/L), and HOMA of insulin resistance (-1.16 in those without insulin treatment [-1.03 in those without diabetes]) were observed after 12 months, whereas no changes were seen in those in the CG.
• At 12 months, IG showed significantly greater improvements in HDL-cholesterol, compared to CG (0.06 vs. 0.0 mmol/L, P<0.001).
• LDL-c decreased in both group, but no between-group differences were observed at 12 months (IG: -0.12 vs. CG: -0.16 mmol/L, P=0.42).
• In participants with diabetes (n=281) improvements in glycemic control (-0.59 vs. 0.22 mmol/L, P<0.001) were observed with the intervention after 12 months, compared to CG.

Conclusion

References

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