. 2017 Oct 19;125(10):107007. doi: 10.1289/EHP1521

Table 1.

Basic characteristics of study participants at baseline.

Variables	Controls ( $n = 1,621$ )	Cases ( $n = 1,621$ )	p-Value^a
Age (years)	$65.6 \pm 7.4$	$65.7 \pm 7.3$	0.72
Male sex, $n$ (%)	789 (48.7)	789 (48.7)
BMI ( ${kg / m}^{2}$ )	$24.23 \pm 3.25$	$24.80 \pm 3.31$	$< 0.001$
Smoking status, $n$ (%)
Current smoker	305 (18.8)	344 (21.2)
Former smoker	179 (11.0)	203 (12.5)	0.06
Never smoker	1137 (70.1)	1074 (66.3)
Pack-years among ever-smokers^b	$29.1 \pm 20.3$	$31.8 \pm 22.6$	0.04
Alcohol intake status, $n$ (%)
Current drinker	360 (22.2)	361 (22.3)
Former drinker	78 (4.8)	70 (4.3)	0.80
Never drinker	1183 (73.0)	1190 (73.4)
Education level, $n$ (%)
Primary school or below	512 (31.6)	543 (33.5)
Middle school	563 (34.7)	597 (36.8)	0.05
High school or beyond	546 (33.7)	481 (29.7)
Physical activity (yes), $n$ (%)^c	1466 (90.4)	1437 (88.6)	0.10
CHD family history, $n$ (%)	77 (4.8)	78 (4.8)	0.93
Hypertension, $n$ (%)^d	699 (43.1)	1074 (66.3)	$< 0.001$
Hyperlipidemia, $n$ (%)^e	711 (43.9)	993 (61.3)	$< 0.001$
Diabetes, $n$ (%)^f	171 (10.5)	383 (23.6)	$< 0.001$
eGFR ( $mL / min / 1.73 m^{2}$ )	$88.00 \pm 21.06$	$84.83 \pm 20.09$	$< 0.001$
eGFR $\geq 90$ , $n$ (%)	648 (40.0)	553 (34.1)	$< 0.001$
Occupational categories
Raw material production	210 (13.0)	229 (14.1)
Automobile parts manufacturing	662 (40.8)	700 (43.2)
Automobile assembly	129 (8.0)	93 (5.7)	0.07
Auxiliary service and management	32 (2.0)	22 (1.4)
Others (e.g., affiliated schools)	564 (34.8)	558 (34.4)
Missing indicator	24 (1.5)	19 (1.2)
Diet categories ( $\geq 5 times / week$ )
Meat	467 (28.8)	423 (26.1)	0.08
Fish or seafood	142 (8.8)	140 (8.6)	0.90
Milk or dairy products	585 (36.1)	558 (34.4)	0.32
Beans or soy foods	420 (25.9)	402 (24.8)	0.47
Fruits or vegetables	1579 (97.4)	1562 (96.4)	0.09

Note: Normally distributed variables were presented as $mean \pm SD$ . Non-normally distributed variables were presented as median (IQR). Categorical variables were presented as numbers (percentage). Data were complete for all variables except occupation. BMI, body mass index; eGFR, estimated glomerular filtration rate.

^{^a}

p-Values were derived from Student’s t-tests or Mann-Whitney U tests for continuous variables according to the data distribution, and chi-square test for the category variables.

^{^b}

Numbers of packs smoked/ $day \times number of years smoked$ , among former and current smokers.

^{^c}

Physical activity was defined as exercise for at least 20 min per week for more than half a year.

^{^d}

Hypertension was defined as measured values $\geq 140 mmHg$ for SBP or $\geq 90 mmHg$ for DBP, self-reported physician diagnosis, or reported use of antihypertensive medication.

^{^e}

Hyperlipidemia was defined as total cholesterol $\geq 5.72 mmol / L$ , triglycerides $\geq 1.70 mmol / L$ , or a self-reported physician diagnosis, or antihyperlipidemia medication use.

^{^f}

Diabetes was defined as fasting glucose $\geq 7.0 mmol / L$ , self-reported physician diagnosis, or antidiabetic medication use (insulin or oral hypoglycemic agents).