Expanded Normal Weight Obesity and Insulin Resistance in US Adults of the National Health and Nutrition Examination Survey

Table 2

Descriptive characteristics of the sample and mean HOMA-IR for each category ().

Categorical variable	N	Weighted %	Mean HOMA	SE	F
eNWO					291.3	<0.0001
Underweight	94	1.9	0.8^a	0.07
Normal weight-low body fat	1624	30.1	1.1^b	0.02
Normal weight-high body fat	288	4.5	1.6^c	0.08
Overweight-low body fat	927	15.9	1.9^d	0.05
Overweight-high body fat	1221	18.3	2.2^e	0.07
Obese-low body fat	141	2.1	3.2^f	0.28
Obese-high body fat	1688	27.2	3.9^g	0.14
Sex					34.2	<0.0001
Men	2939	50.8	2.5^a	0.09
Women	3044	49.2	2.0^b	0.05
Race					15.0	<0.0001
Non-Hispanic White	2468	55.8	2.2^a	0.09
Non-Hispanic Black	847	7.9	2.5^b,d	0.07
Mexican American	1072	5.5	2.6^c,d	0.08
Other races	1401	26.8	2.3^a	0.08
Other Hispanics	195	3.9	2.4^d	0.23
Year of assessment					4.0	0.0114
1999–2000	1489	23.1	2.2^a,b	0.08
2001–2002	1679	26.9	2.1^b,c	0.06
2003–2004	1540	26.0	2.5^a	0.16
2005–2006	1275	23.9	2.3^c	0.09
Moderate physical activity					14.2	0.0004
Yes	3055	45.0	2.2^a	0.07
No	2928	55.0	2.4^b	0.06
Vigorous physical activity					30.1	<0.0001
Yes	2000	38.2	2.0^a	0.06
No	3983	61.8	2.4^b	0.07

NWO = expanded normal weight obesity category. Low body fat is defined as below the overall sex-specific median, and high body fat is defined as above the overall sex-specific median. The unweighted sample size (N) and the survey-weighted proportion (weighted %) of each subgroup are included. Focus should be on the survey-weighted proportions because they represent the US adult population. Summing the weighted % values may not equal to 100% due to rounding; The F values reflect mean HOMA-IR differences across each categorical variable without adjusting for any covariates. For each variable, means with the same superscript letters a, b, c, d, e, f, and g in the mean HOMA column are not significantly different (). Mean (±SE) age was 43.8 ± 0.4 years, and mean number of smoking pack-years was 0.8 ± 0.1. Among current smokers, the average number of cigarettes smoked per day was 17.9 ± 0.6.