Table 2.

Association between obesity according to Fat Mass Index (FMI) from 18 to 22 years on bone mineral density (g/cm²) at 22 years of age

Variable	Men (N = 1408)
	N	Whole Body		Lumbar Spine		Femoral Neck
		Mean	Adjusteda	Mean	Adjusteda	Mean	Adjusteda
		(95% CI)	β (95% CI)	(95% CI)	β (95% CI)	(95% CI)	β (95% CI)
Obesity by FMI			0.332		0.140		0.088
Never	1139	1.263	Reference	1.232	Reference	1.169	Reference
		(1.257; 1.268)		(1.224; 1.241)		(1.159; 1.179)
Only at 18 years	28	1.297	0.008	1.304	0.007	1.188	0.021
		(1.263; 1.331)	(−0.020; 0.005)	(1.251; 1.357)	(−0.016; 0.031)	(1.128; 1.249)	(−0.013; 0.055)
Only at 22 years	158	1.300	0.002	1.249	−0.007	1.204	0.015
		(1.286; 1.313)	(−0.004; 0.008)	(1.228; 1.270)	(−0.017; 0.004)	(1.179; 1.228)	(−0.001; 0.030)
Always	83	1.313	0.005	1.242	−0.014	1.208	0.018
		(1.295; 1.331)	(−0.003; 0.012)	(1.216; 1.268)	(−0.029; − 0.001)	(1.175; 1.241)	(− 0.003; 0.038)
Variable	Women (N = 1560)
	N	Whole Body		Lumbar Spine		Femoral Neck
		Mean	Adjusteda	Mean	Adjusteda	Mean	Adjusteda
		(95% CI)	β (95% CI)	(95% CI)	β (95% CI)	(95% CI)	β (95% CI)
Obesity by FMI			<0.001		0.339		0.001
Never	1208	1.142	Reference	1.185	Reference	1.007	Reference
		(1.138; 1.146)		(1.178; 1.192)		(1.000; 1.014)
Only at 18 years	23	1.183	−0.013	1.239	−0.005	1.036	−0.014
		(1.153; 1.212)	(− 0.023; − 0.002)	(1.192; 1.285)	(− 0.027; 0.018)	(0.989; 1.083)	(− 0.042; 0.014)
Only at 22 years	182	1.192	0.013	1.228	0.007	1.080	0.027
		(1.182; 1.202)	(0.009; 0.017)	(1.210; 1.247)	(−0.001; 0.016)	(1.063; 1.097)	(0.016; 0.038)
Always	147	1.236	0.005	1.286	−0.001	1.129	0.006
		(1.225; 1.248)	(0.001; 0.011)	(1.266; 1.305)	(−0.012; 0.010)	(1.109; 1.149)	(−0.008; 0.019)

^aAdjusted for perinatal variables (maternal nutritional status, family income, maternal education, gestational age, weight and length), 15 years (skin color), 18 years (smoking, total physical activity score, calcium intake) and 22 years of age (lean mass index)

The 1993 Birth Cohort, Pelotas, Brazil