Table 2.

The observational association of long-term exposure to ${\mathrm{PM}}_{2.5}$ with BMD measured after the year 2010 in males ($n=\mathrm{18,591}$ for heel BMD; $n=\mathrm{14,798}$ for lumbar spine 1 to 4 BMD; $n=\mathrm{14,798}$ for femur neck BMD) and females ($n=\mathrm{18,849}$ for heel BMD; $n=\mathrm{14,968}$ for lumbar spine 1 to 4 BMD; $n=\mathrm{14,968}$ for femur neck BMD) in the UK Biobank.

	$\mathrm{\beta }\text{-coefficient}$ a	SE	$p$-Valueb
Heel BMD
Male
Model 1	$-0.004$	0.001	$1.68\times {10}^{-5}$
Model 2	$-0.003$	0.001	0.001
Female
Model 1	$-0.002$	0.001	0.001
Model 2	$-0.002$	0.001	0.036
Lumbar spine 1 to 4 BMD
Male
Model 1	$-0.007$	0.001	$1.54\times {10}^{-6}$
Model 2	$-0.006$	0.002	$2.19\times {10}^{-4}$
Female
Model 1	$-0.004$	0.001	0.004
Model 2	$-0.003$	0.001	0.027
Femur neck BMD (right)
Male
Model 1	$-0.004$	0.001	$6.84\times {10}^{-5}$
Model 2	$-0.003$	0.001	0.004
Female
Model 1	$-0.002$	0.001	0.055
Model 2	$-0.002$	0.001	0.113

Note: Model 1 was adjusted for confounders, including age, body mass index, and ancestry; $\text{model\hspace{0.17em}}2=\text{model\hspace{0.17em}}1+\text{education}+\text{smoking}+\text{alcohol}+\text{physical activity}+\text{circulating calcium}+\text{calcium}$ supplementary status. BMD, bone mineral density; ${\mathrm{PM}}_{2.5}$, particulate matter with aerodynamic diameter of $\le 2.5\mathrm{\mu }\mathrm{m}$; SE, standard error.

^a The $\mathrm{\beta }\text{-coefficient}$ represents the change in BMD in grams per centimeter squared for a $1\text{-}{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$ increase in annual ${\mathrm{PM}}_{2.5}$ concentrations.

^b All $p$-values were derived from multiple linear regression.