SUPPLEMENTAL MATERIAL
Stenhom S et al. Patterns of Weight Gain in Middle-Aged and Older US Adults in 1992-2010. Epidemiology 2014, 00:000-000.
Analyses aggregated across study periods
We graphically examined changes in the BMI distribution from 1992 to 2010 in the longitudinal and cross-sectional data by using Tukey mean-difference plots (m-d plots), as previously suggested 1-3. An m-d plot is useful in the analysis of data with a strong correlation between two distributions because it is able to show the direction and magnitude of the shift between distributions. eFigure 1, Panel A shows that based on longitudinal data there was a prominent increase in BMI among persons belonging to the normal-weight and overweight range.
The participants with an average BMI>30 kg/m2 show less increase in their BMIs, and those in the 95th BMI percentile show a decrease in BMI during the 6-year follow-up. The pattern is different in cross-sectional data (Panel B). At the population level, the increase in BMI is relatively small in the lower
segments, but large in the upper segments of the initial BMI distribution. These population-level findings are in agreement with previous analyses 1,4-9.
Subgroup analyses
We examined whether there were differences in patterns of BMI changes according to age, sex and race by including BMI x period x age / sex / race interaction terms in the model. There were no significant differences in how weight changed by initial BMI status across age, sex or race groups (eTable 1).
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Figure 1. Mean difference (m-d) plots of the BMI distribution for each 5 percentile category at baseline and at the 6-year follow-up, based on repeated longitudinal individual level data (Panel A) and repeated cross-sectional data (Panel B) (N = 15 895)*.
A: Longitudinal data B: cross-sectional data
eTable 1. Six-year Change in BMI According to Period and Baseline BMI and Separately by Sex, Age Group and Race.
Underweight Normal weight Overweight Obesity class I Obesity class II Obesity class III
N Mean 95% CL Mean 95% CL Mean 95% CL Mean 95% CL Mean 95% CL Mean 95% CL
Total study population
1992/1994-1998/2000 9645 0.25 -0.32 0.83 0.27 0.15 0.38 0.22 0.12 0.33 0.003 -0.15 0.16 -0.43 -0.70 -0.16 -1.59 -2.00 -1.18 1996/1998-2002/2004 10844 0.44 -0.15 1.04 0.39 0.28 0.50 0.34 0.24 0.44 0.18 0.05 0.32 -0.09 -0.32 0.14 -1.42 -1.77 -1.07 2000/2002-2006/2008 9381 0.43 -0.32 1.18 0.54 0.42 0.66 0.53 0.42 0.64 0.31 0.17 0.45 -0.07 -0.31 0.16 -1.20 -1.53 -0.86 2004-2010 8891 1.03 0.25 1.82 0.50 0.37 0.63 0.57 0.46 0.67 0.35 0.21 0.48 -0.24 -0.45 -0.02 -1.42 -1.72 -1.12 Men
1992/1994-1998/2000 4217 -0.21 -1.19 0.78 0.14 0.01 0.26 0.13 0.00 0.25 -0.12 -0.35 0.10 -0.21 -0.74 0.32 -3.98 -8.10 0.15 1996/1998-2002/2004 4660 -0.09 -1.06 0.87 0.33 0.20 0.46 0.24 0.12 0.36 0.09 -0.10 0.28 0.28 -0.20 0.75 -1.74 -2.95 -0.54 2000/2002-2006/2008 3888 -0.29 -1.59 1.02 0.36 0.20 0.52 0.31 0.18 0.44 0.20 -0.03 0.43 -0.22 -0.70 0.26 -0.90 -2.35 0.54 2004-2010 3684 1.66 -1.32 4.64 0.42 0.26 0.59 0.46 0.32 0.60 0.34 0.14 0.54 -0.37 -0.87 0.14 -0.64 -1.96 0.68 Women
1992/1994-1998/2000 5428 0.42 -0.04 0.87 0.38 0.26 0.50 0.32 0.17 0.47 0.12 -0.13 0.37 -0.49 -1.07 0.08 -1.05 -2.00 -0.09 1996/1998-2002/2004 6184 0.58 0.20 0.96 0.45 0.34 0.57 0.43 0.30 0.56 0.28 0.06 0.49 -0.23 -0.64 0.19 -1.25 -2.01 -0.49 2000/2002-2006/2008 5493 0.59 0.03 1.16 0.68 0.55 0.80 0.72 0.57 0.88 0.41 0.18 0.64 0.05 -0.43 0.53 -1.20 -2.10 -0.31 0.99 0.31 1.67 0.58 0.44 0.72 0.66 0.50 0.82 0.37 0.14 0.60 -0.12 -0.53 0.30 -1.64 -2.50 -0.77
Age group 40-49 years
1992/1994-1998/2000 876 0.63 -0.32 1.59 0.75 0.42 1.08 0.73 0.33 1.14 0.29 -0.40 0.98 -0.59 -1.86 0.68 -0.74 -2.69 1.21 1996/1998-2002/2004 629 2.04 1.20 2.89 0.87 0.45 1.28 0.68 0.25 1.10 0.89 0.15 1.63 -0.83 -2.17 0.52 -3.10 -5.36 -0.85 2000/2002-2006/2008 370 2.85 -0.30 5.99 0.71 0.26 1.17 1.25 0.58 1.91 1.12 0.00 2.24 -0.42 -2.28 1.44 -3.84 -7.29 -0.40 2004-2010 502 -1.20 -1.62 -0.78 0.98 0.52 1.43 1.00 0.49 1.51 0.17 -0.50 0.85 -0.50 -2.01 1.01 0.59 -1.74 2.91 Age group 50-59
years
1992/1994-1998/2000 6362 0.31 -0.25 0.87 0.44 0.32 0.55 0.43 0.30 0.55 0.16 -0.05 0.36 -0.06 -0.59 0.47 -1.47 -2.91 -0.02 1996/1998-2002/2004 5652 0.41 -0.16 0.98 0.57 0.45 0.70 0.54 0.41 0.66 0.31 0.12 0.51 0.37 -0.06 0.79 -1.21 -2.07 -0.35 2000/2002-2006/2008 3381 -0.39 -0.99 0.20 0.64 0.49 0.80 0.58 0.43 0.73 0.26 0.00 0.52 0.50 -0.02 1.02 -1.32 -2.40 -0.24 2004-2010 3597 1.34 0.16 2.52 0.50 0.33 0.67 0.77 0.61 0.94 0.58 0.36 0.80 0.08 -0.45 0.60 -1.13 -2.23 -0.04 Age group 60-69
years
1992/1994-1998/2000 2407 0.20 -0.59 0.98 -0.11 -0.26 0.05 -0.19 -0.36 -0.01 -0.17 -0.50 0.15 -0.88 -1.69 -0.08 -2.00 -4.02 0.03 1996/1998-2002/2004 4563 0.28 -0.17 0.74 0.08 -0.04 0.21 0.05 -0.09 0.18 -0.07 -0.31 0.16 -0.50 -0.99 -0.01 -1.23 -2.26 -0.20
0.78 0.12 1.45 0.34 0.20 0.47 0.33 0.19 0.47 0.19 -0.03 0.40 -0.52 -1.00 -0.03 -0.70 -1.81 0.41
White
1992/1994-1998/2000 7860 0.34 -0.14 0.81 0.41 0.34 0.47 0.39 0.31 0.47 0.24 0.06 0.42 -0.30 -0.81 0.21 -1.38 -2.53 -0.23 1996/1998-2002/2004 8860 0.60 0.22 0.99 0.52 0.45 0.59 0.46 0.39 0.54 0.35 0.20 0.49 0.09 -0.29 0.47 -1.76 -2.54 -0.99 2000/2002-2006/2008 7616 0.59 0.07 1.10 0.70 0.61 0.79 0.66 0.57 0.76 0.43 0.26 0.60 -0.03 -0.44 0.39 -0.90 -1.82 0.02 2004-2010 7050 0.86 0.26 1.45 0.67 0.57 0.76 0.76 0.66 0.86 0.49 0.33 0.64 0.10 -0.27 0.48 -0.85 -1.76 0.05 Black
1992/1994-1998/2000 1443 0.64 -0.37 1.65 0.27 0.00 0.55 0.16 -0.09 0.42 -0.18 -0.55 0.18 -0.31 -1.09 0.46 -1.78 -4.04 0.47 1996/1998-2002/2004 1555 0.21 -0.81 1.23 0.54 0.26 0.82 0.43 0.21 0.66 0.01 -0.32 0.35 -0.07 -0.66 0.52 -0.58 -1.87 0.71 2000/2002-2006/2008 1379 0.03 -2.99 3.04 0.44 0.12 0.77 0.73 0.46 1.00 0.30 -0.10 0.70 0.01 -0.71 0.72 -1.27 -2.80 0.25 2004-2010 1311 0.30 -1.85 2.46 0.48 0.08 0.89 0.32 0.05 0.59 0.28 -0.16 0.72 -0.77 -1.45 -0.09 -2.09 -3.39 -0.79 Other
1992/1994-1998/2000 340 0.47 -0.70 1.65 0.54 0.03 1.06 -0.07 -0.57 0.43 -1.40 -2.72 -0.08 -1.05 -3.13 1.03 -2.73 -6.18 0.73 1996/1998-2002/2004 429 0.60 -1.01 2.20 0.46 0.10 0.82 0.33 -0.03 0.70 0.71 -0.15 1.56 -1.09 -2.52 0.33 -0.83 -2.32 0.66 2000/2002-2006/2008 386 0.79 -0.81 2.38 0.68 0.34 1.01 0.04 -0.38 0.46 0.83 -0.02 1.68 1.36 -0.40 3.12 -2.71 -5.23 -0.19 2004-2010 530 5.33 0.05 10.60 0.31 -0.09 0.71 0.44 -0.01 0.90 0.56 -0.12 1.23 -0.69 -2.04 0.66 -2.40 -5.19 0.40
Notes: All models were adjusted for age, sex, ethnicity, and education. Interaction term for age* BMI*period p = 0.15, sex* BMI*period p = 0.80, race*BMI*period p=0.33.