Introduction
Methods
Literature search
Keywords | MEDLINE | EMBASE |
---|---|---|
Diet, exercise, obese, diabetes risk, men, women | 27 | 56 |
Diet, exercise, overweight, diabetes risk, men, women | 29 | 50 |
Diet, exercise, obese, cardiovascular risk, men, women | 32 | 63 |
Diet, exercise, overweight, cardiovascular risk, men, women | 34 | 69 |
Diet, physical activity, obese, diabetes risk, men, women | 29 | 67 |
Diet, physical activity, overweight, diabetes risk, men, women | 28 | 84 |
Diet, physical activity, obese, cardiovascular risk, men, women | 33 | 77 |
Diet, physical activity, overweight, cardiovascular risk, men, women | 31 | 97 |
Weight loss, exercise, obese, diabetes risk, men, women | 18 | 21 |
Weight loss , exercise, overweight, diabetes risk, men, women | 17 | 32 |
Data and variables
Study | Authors and year | Country | Age1 | Women2 | IGT/IR/MetS3 | BMI4 | Diet intervention guidelines5 | Exercise intervention guidelines5 |
---|---|---|---|---|---|---|---|---|
1 | Straznicky et al. 2012 [20] | Australia | 55 | 0.41 | MS | 32.7 | ~650 kcal/d restriction, 22% protein, 30% TF, 9% SF | aerobic (biking), 40 min/S, 3–4 S/wk |
2 | Blumenthal et al. 2010 [21] | USA | 52 | 0.69 | NA | 33.3 | ~500 kcal/d restriction, 27% TF | aerobic (biking and walking), 40 min/S, 3–4 S/wk |
3 | Ibanez et al. 2010 [22] | Spain | 50 | 1.00 | NA | 35.0 | 500 kcal/d restriction | resistance training, 45–60 min/S, 2 S/wk |
4 | Straznicky et al. 2010 [23] | Australia | 55 | 0.41 | MS | 32.4 | ~500 kcal/d restriction, 30% TF, 9% SF | aerobic (biking), 40 min/S, 3 S/wk |
5 | Roumen et al. 2008 [24] | Netherlands | 56 | 0.45 | IGT | 29.4 | reduced caloric and reduced fat diet | aerobic plus resistant training, 30 min/S, 5 S/wk |
6 | Herder et al. 2009 [25] | Finland | 56 | 0.50 | IGT | 31.2 | <30% TF, <10% SF | endurance training, >30 min/S, ~6 S/wk |
7 | Mosca et al. 2008 [26] | USA | 48 | 0.66 | NA | 28.1 | low-SF and low-cholesterol diet | moderate physical activity (brisk walking), 30–60 min/S |
8 | Morgan et al. 2009 [27] | UK | 41 | 0.74 | NA | 31.6 | Rosemary Conley's controlled-calorie low-fat diet | Rosemary Conley's Fitness plan with weekly classes |
9 | Dale et al. 2009 [28] | New Zealand | 46 | 0.67 | IR | 34.6 | 400 kcal/d restriction, 27% TF, 9% SF | high intensity training, 30 min/S, 5 S/wk |
10 | Meckling and Sherfey, 2007 [29] | Canada | 43 | 1.00 | NA | 29.9 | 500 kcal/d restriction, high protein (37%) diet | endurance training, 36 min/S, 3 S/wk |
11 | Burke et al. 2007 [30] | Australia | 56 | 0.56 | NA | 30.1 | <30% TF, <10% SF | moderate intensity, 30 min/S, most days/wk |
12 | Bo et al. 2007 [31] | Italy | 56 | 0.58 | MS | 30.0 | reduced TF and SF intake | moderate intensity (i. e. brisk walking), ~150 min/wk |
13 | Arciero et al. 2006 [32] | USA | 43 | 0.48 | NA | 27.8 | high protein (40%) and low fat (20%) diet | resistance and cardiovascular training, 20 min/S, 4–6 S/wk |
14 | Brekke et al. 2005 [33] | Sweden | 42 | 0.37 | NA | 26.1 | <30% TF intake, <10% SF intake | walking or more intensive exercise, 30 min/S, 4–5 S/wk |
15 | Watkins et al. 2003 [34] | USA | 50 | 0.50 | NA | 33.7 | 500 kcal/d restriction, <20% TF | cycle ergometry and jogging, or walking, ~60 min/S, 3–4 S/wk |
16 | Lindstrom et al. 2003 [35] | Finland | 55 | 0.66 | IGT | 31.3 | 200 kcal/d restriction, <30% TF, <10% SF | endurance exercise & resistance training, >30 min/S |
17 | Esposito et al. 2003 [36] | Italy | 35 | 1.00 | NA | 34.5 | 1400 kcal/d, 55% carbohydrate, 30% TF, <10% SF | aerobic exercise (walking and swimming) |
18 | Mensink et al. 2003 [37] | Netherlands | 56 | 0.43 | IGT | 29.5 | >55% carbohydrate, <30% TF, <10% SF | moderate physical activity, >30 min/S, 5 S/wk |
19 | McAuley et al. 2002 [38] | New Zealand | 46 | 0.71 | IR | 34.5 | 400 kcal/d restriction, 27% TF, 9% SF | Moderate exercise plus resistance training, >20 min/S, 5 S/wk |
20 | Miller et al. 2002 [39] | USA | 54 | 0.62 | NA | 33.7 | 500 kcal/d restriction, 27% TF, 6% SF | aerobic (brisk walking and biking), 30–45 min/S, 3 S/wk |
21 | Reseland et al. 2001 [40] | Norway | 45 | 0.00 | MS | 27.5 | 400 kcal/d restriction, <30% TF | endurance exercise, 1 h/S, 3 S/wk |
22 | Oldroyd et al. 2001 [41] | UK | 58 | 0.40 | IGT | 30.2 | <30% TF intake, ~50% carbohydrate | aerobic exercise, 20–30 min/S, 2–3 S/wk |
23 | Kuller et al. 2001 [42] | USA | 47 | 1.00 | NA | 25.0 | Calorie restriction upto 1300 kcal, 25% TF, 7% SF | increasing physical activity to 1250 kcal expended weekly |
24 | Ornish et al. 1998 [43] | USA | 60 | 0.09 | NA | 26.9 | 10%-fat vegetarian diet | moderate-intensity aerobic, 1 h/S, 5 S/wk |
25 | Stefanick et al. 1998 (female) [16] | USA | 57 | 1.00 | NA | 25.6 | <30% TF intake, <7% SF intake | aerobic (jogging and brisk walking), 60 min/S, 3 S/wk |
26 | Stefanick et al. 1998 (male) [16] | USA | 48 | 1.00 | NA | 27.8 | <30% TF intake, <7% SF intake | aerobic (jogging and brisk walking), 60 min/S, 3 S/wk |
27 | Wing et al. 1998 [44] | USA | 46 | 0.78 | NA | 36.0 | 600-700 kcal/d restriction, 20% TF intake | aerobic (brisk walking), 60 min/S, 5 S/wk |
28 | Simkin-Silverman et al. 1995 [45] | UK | 47 | 1.00 | NA | 25.1 | <25% TF intake, <7% SF intake | brisk walking spending 1000 kcal/wk, 3–5 S/wk |
29 | Hellenius et al. 1993 [46] | Sweden | 46 | 0.00 | NA | 25.6 | 12% daily calorie and 10% TF restriction | aerobic exercise, 30–45 min/S, 2–3 S/wk |
30 | Svendsen et al. 1993 [47] | Denmark | 54 | 1.00 | NA | 29.7 | 800 kcal/d restriction, low fat (25%) diet | aerobic plus resistant training, 75 min/S, 3 S/wk |
31 | Page et al. 1993 [48] | UK | 40 | 0.23 | IGT | 25.9 | 50-55% carbohydrate, 30% TF, high fiber | aerobic weight and circuit training, swimming, >3 S/wk |
32 | Schuler et al. 1992 [49] | Germany | 54 | 0.00 | NA | 26.6 | <20% TF, 65% carbohydrate, PUSF: SF ratio >1.0 | daily exercise (75% MHR), >30 min/S |
33 | Wood et al. 1991 (male) [17] | USA | 38 | 0.00 | NA | 33.5 | 55% carbohydrate, 30% TF, <10% SF | aerobic (brisk walking and jogging), 35 min/S, 3 S/wk |
34 | Wood et al. 1991 (female) [17] | USA | 38 | 1.00 | NA | 26.3 | 55% carbohydrate, 30% TF, <10% SF | aerobic (brisk walking and jogging), 35 min/S, 3 S/wk |
Statistical analyses
Variable | Mean ± SD1 | Minimum | Maximum |
---|---|---|---|
Energy and macronutrient intake at baseline
| |||
Calorie intake, kcal/d | 2100 ± 260 | 1583 | 2900 |
Carbohydrate, %E | 46.6 ± 5.0 | 36.5 | 58.5 |
Protein, %E | 17.2 ± 2.6 | 12.3 | 25 |
Fat, %E | 34.7 ± 3.3 | 27.5 | 43.5 |
Saturated fat, %E | 12.9 ± 1.8 | 9 | 16.6 |
Energy and macronutrient intake changes of intervention participants
2
| |||
Calorie intake, kcal/d | -273 ± 169 | -828 | 49.5 |
Carbohydrate, %E | 2.9 ± 5.7 | -14 | 11 |
Protein, %E | 3.3 ± 5.6 | -3.8 | 21.3 |
Fat, %E | -6.3 ± 3.8 | -16.5 | 0.4 |
Saturated fat, %E | -2.9 ± 2.0 | -8 | 0.0 |
Exercise intervention
| |||
Number of sessions per week | 4 ± 1.0 | 2 | 7 |
Session length (minutes) | 41 ± 13 | 20 | 75 |
Risk factor level measurements at baseline
| |||
FI | 14.9 ± 5.4 | 3.0 | 24.1 |
FG | 5.55 ± 0.4 | 4.83 | 6.20 |
SBP | 128 ± 10 | 110 | 143 |
HDL | 1.25 ± 0.2 | 0.89 | 1.74 |
TAG | 1.76 ± 0.9 | 0.85 | 5.84 |
BMI | 30.2 ± 3.3 | 25.0 | 36.0 |
Age at baseline, years | 49 ± 7 | 35 | 60 |
Fraction of women participants | 0.59 ± 0.3 | 0 | 1 |
Duration of intervention (months)3 | 14 ± 3.5 | 2 | 60 |
Publication bias and influence diagnosis
Results
Study characteristics
Heterogeneity
Risk factor1 | Number of studies included | N2 | Heterogeneity2 | Funnel plot asymmetry ( P-value)3 | ||
---|---|---|---|---|---|---|
I
2
(%)2 |
τ
2
| P-value | ||||
FI (mU/L) | 18 | 1756 | 99.5 | 3.762 ± 1.511 | <0.001 | 0.519 |
FG (mmol/L) | 24 | 3897 | 99.4 | 0.013 ± 0.005 | <0.001 | 0.774 |
SBP (mm Hg) | 23 | 3443 | 99.4 | 7.474 ± 2.894 | <0.001 | 0.771 |
HDL (mmol/L) | 30 | 4218 | 99.8 | 0.007 ± 0.002 | <0.001 | 0.577 |
TAG (mmol/L) | 29 | 3908 | 99.8 | 0.050 ± 0.015 | <0.001 | 0.855 |
BMI (kg/m2) | 29 | 4160 | 99.8 | 0.881 ± 0.256 | <0.001 | 0.587 |
Intervention effect size estimates from mixed-effect models
Risk factor1 | Overall effect size | Effect size change for intervention attributes and other factors | Residual heterogeneity | ||||
---|---|---|---|---|---|---|---|
Estimate ± SE | P- value | Explanatory Variables2 | Estimate ± SE3 | P-value | τ2 | P-value | |
FI (mU/L) | -2.56 ± 0.58 | <0.001 | Presence of IGT, IR or MetS | -1.20 ± 0.69 | 0.082 | 1.523 ± 0.773 | <0.001 |
Calorie restriction (100 kcal/d) | -0.68 ± 0.26 | 0.009 | |||||
Incorporation of resistance training | 1.72 ± 0.81 | 0.034 | |||||
FG (mmol/L) | -0.18 ± 0.04 | <0.001 | Presence of IGT, IR or MetS | -0.08 ± 0.05 | 0.098 | 0.010 ± 0.004 | <0.001 |
After a follow-up period | 0.13 ± 0.06 | 0.034 | |||||
SBP (mm Hg) | -2.77 ± 0.56 | <0.001 | Presence of IGT, IR or MetS | -3.23 ± 1.00 | 0.001 | 2.796 ± 1.419 | <0.001 |
Calorie restriction (100 kcal/d) | -0.64 ± 0.23 | 0.006 | |||||
Length of intervention (months) | 0.13 ± 0.03 | <0.001 | |||||
HDL (mmol/L) | -0.015 ± 0.015 | 0.305 | Age at baseline (years) | -0.006 ± 0.002 | 0.021 | 0.005 ± 0.002 | <0.001 |
Fraction of women participants | -0.086 ± 0.046 | 0.065 | |||||
TAG (mmol/L) | -0.258 ± 0.037 | <0.001 | Calorie restriction (100 kcal/d) | -0.061 ± 0.017 | <0.001 | 0.029 ± 0.009 | <0.001 |
Baseline TAG (mmol/L) | -0.243 ± 0.076 | 0.001 | |||||
BMI (kg/m2) | -1.61 ± 0.13 | <0.001 | Calorie restriction (100 kcal/d) | -0.22 ± 0.08 | 0.003 | 0.353 ± 0.125 | <0.001 |
Fat intake restriction (% Energy) | -0.10 ± 0.03 | 0.003 | |||||
Exercise session duration (10 min) | -0.24 ± 0.12 | 0.055 | |||||
Baseline BMI (kg/m2) | -0.07 ± 0.04 | 0.095 |