Ten-year changes in the prevalence of overweight, obesity and central obesity among the Chinese adults in urban Shanghai, 1998–2007 — comparison of two cross-sectional surveys

Table 2 Standardized means of body mass index and waist circumference in 1998–2001 and 2007–2008

Population	N₁	N₂	BMI (kg/m²)			Waist circumference (cm)
Population	1998-2001	2007-2008	1998-2001	2007-2008	Difference^e	1998-2001	2007-2008	Difference^e
Standardized
Overall^a	4894	4395	23.3	23.6	0.2	77.7	79.9	1.4
Men^b	2081	1599	23.5	24.1	0.5	81.1	83.9	2.6
Women^b	2813	2796	23.0	23.1	−0.1	74.1	75.7	1.3
p values for difference^c			0.257	p < 0.001		p < 0.001	p < 0.001
Sex- and age-specific
Men
20-29 years	225	199	23.3 (4.2)	23.3 (3.8)	0	78.3 (11.1)	80.2 (10.7)	1.9
30-39 years	406	235	23.2 (3.3)	24.3 (3.5)	1.1	80.4 (9.3)	83.5 (8.9)	3.1
40-49 years	522	282	23.3 (3.1)	24.7 (3.1)	1.4	81.7 (9.4)	86.6 (8.7)	4.9
50-59 years	284	457	24.1 (3.1)	24.4 (3.2)	0.3	83.9 (9.5)	85.8 (8.8)	1.9
60-74 years	644	426	24.2 (3.2)	24.2 (3.0)	0	84.8 (9.5)	85.8 (9.0)	1
p values for linear trend^d			p < 0.001	0.058		p < 0.001	p < 0.001
Women
20-29 years	225	249	21.2 (3.0)	21.6 (3.1)	0.4	67.6 (7.7)	70.8 (7.8)	3.2
30-39 years	561	427	22.8 (3.4)	22.8 (3.3)	0	73.0 (8.4)	73.8 (8.3)	0.8
40-49 years	841	590	23.5 (3.2)	23.8 (3.2)	0.3	75.5 (8.3)	78.2 (8.5)	2.7
50-59 years	385	968	24.5 (3.5)	24.1(3.4)	−0.4	79.0 (9.2)	79.8 (8.7)	0.8
60-74 years	801	562	25.2 (3.7)	24.5 (3.5)	−0.7	82.8 (9.9)	82.0 (9.0)	−0.8
p values for linear trend^d			p < 0.001	p < 0.001		p < 0.001	p < 0.001

Data are expressed as the means (with standard deviations).
Means were standardized by the direct method according to the Chinese population structure in 2000.
^aAdjusted for age and sex.
^bAdjusted for age.
^cDifferences in means were tested using an age-adjusted covariance analysis.
^dLinear trends for age-specific means were tested using linear regression analyses; age group was treated as a continuous variable.
^eThe differences are calculated as the mean for the 2007–2008 survey minus the mean for the 1998–2001 survey.
Abbreviations: BMI: body mass index.

ISSN: 1471-2458