Diet and Exercise Interventions among Overweight and Obese Lactating Women: Randomized Trial of Effects on Cardiovascular Risk Factors

Objective
To examine the effects of Diet (D) and Exercise (E) interventions on cardiovascular fitness, waist circumference, blood lipids, glucose metabolism, inflammation markers, insulin-like growth factor 1 (IGF-1) and blood pressure in overweight and obese lactating women.
Methods
At 10–14 wk postpartum, 68 Swedish women with a self-reported pre-pregnancy BMI of 25–35 kg/m2 were randomized to a 12-wk behavior modification treatment with D, E, both or control using a 2×2 factorial design. The goal of D treatment was to reduce body weight by 0.5 kg/wk, accomplished by decreasing energy intake by 500 kcal/d and monitoring weight loss through self-weighing. The goal of E treatment was to perform 4 45-min walks per wk at 60–70% of max heart-rate using a heart-rate monitor. Effects were measured 12 wk and 1 y after randomization. General Linear Modeling was used to study main and interaction effects adjusted for baseline values of dependent variable.
Results
There was a significant main effect of the D treatment, decreasing waist circumference (P = 0.001), total cholesterol (P = 0.007), LDL-cholesterol (P = 0.003) and fasting insulin (P = 0.042), at the end of the 12-wk treatment. The decreased waist circumference (P<0.001) and insulin (P = 0.024) was sustained and HDL-cholesterol increased (P = 0.005) at the 1-y follow-up. No effects from the E treatment or any interaction effects were observed.
Conclusions
Dietary behavior modification that produced sustained weight loss among overweight and obese lactating women also improved risk factors for cardiovascular disease and type 2 diabetes. This intervention may not only reduce weight-related risks with future pregnancies but also long-term risk for metabolic disease.
Trial registration
ClinicalTrials.gov NCT01343238

研究目的
探究饮食（Diet, D）与运动（Exercise, E）干预对超重肥胖哺乳期女性的心血管适能、腰围、血脂、糖代谢、炎症标志物、胰岛素样生长因子1（insulin-like growth factor 1, IGF-1）及血压的影响。

方法
于产后10~14周，纳入68名自我报告孕前体重指数（body mass index, BMI）为25~35 kg/m²的瑞典女性，采用2×2析因设计（2×2 factorial design）随机分为12周行为矫正干预组，包括单纯饮食干预、单纯运动干预、联合干预及对照组。饮食干预目标为每周减重0.5 kg，通过每日减少500 kcal能量摄入并通过自我称重监测减重效果实现。运动干预目标为每周进行4次、每次45分钟的步行运动，运动强度维持在最大心率的60%~70%，需佩戴心率监测仪。分别于随机分组后12周及1年时评估干预效果。采用一般线性模型（General Linear Modeling）分析校正因变量基线值后的主效应与交互效应。

结果
12周干预结束时，饮食干预可产生显著主效应，可降低腰围（P=0.001）、总胆固醇（P=0.007）、低密度脂蛋白胆固醇（LDL-cholesterol, P=0.003）及空腹胰岛素（P=0.042）。随访至1年时，腰围降低与空腹胰岛素水平降低的效果得以维持，同时高密度脂蛋白胆固醇（HDL-cholesterol）水平升高（P=0.005）。未观察到运动干预的显著效应或任何交互效应。

结论
可使超重肥胖哺乳期女性实现持续减重的饮食行为矫正干预，还可改善心血管疾病与2型糖尿病的危险因素。该干预不仅可降低未来妊娠期间与体重相关的疾病风险，还可降低代谢性疾病的长期发病风险。

试验注册
ClinicalTrials.gov NCT01343238