. 2023 Jan 4;131(1):017001. doi: 10.1289/EHP10611

Table 2.

Summary statistics of concentrations of air pollutants (2005–2015) and incidence of metabolic syndrome and its components in the MJ Health Research cohort by region between 2006 and 2016, Taiwan.

Statistics	Cohort without abdominal obesity ( $uppercase italic n equals 77,862$ )	Cohort with normal TG ( $uppercase italic n equals 76,101$ )	Cohort with normal HDL-C ( $uppercase italic n equals 74,488$ )	Cohort with normal BP ( $uppercase italic n equals 69,871$ )	Cohort with normal FBG ( $uppercase italic n equals 59,681$ )	Cohort without MetS ( $uppercase italic n equals 76,349$ )
1-y average concentration for the year before health check-up ( $mean \pm SD$ )
${PM}_{2.5}$ ( ${μ g / m}^{3}$ )
North	$27.67 \pm 4.65$	$27.71 \pm 4.66$	$27.49 \pm 4.72$	$27.74 \pm 4.67$	$27.93 \pm 4.61$	$27.61 \pm 4.68$
Central	$33.97 \pm 3.81$	$34.00 \pm 3.84$	$33.98 \pm 3.81$	$34.06 \pm 3.82$	$34.19 \pm 3.77$	$33.99 \pm 3.82$
South	$42.77 \pm 4.03$	$42.82 \pm 4.05$	$42.73 \pm 4.05$	$42.86 \pm 4.00$	$42.89 \pm 3.99$	$42.76 \pm 4.04$
Total	$31.30 \pm 7.33$	$31.05 \pm 7.22$	$31.18 \pm 7.37$	$30.94 \pm 7.13$	$31.48 \pm 7.13$	$31.13 \pm 7.28$
${NO}_{2}$ (ppb)
North	$20.41 \pm 5.06$	$20.48 \pm 5.08$	$20.35 \pm 5.13$	$20.48 \pm 5.05$	$20.63 \pm 5.03$	$20.42 \pm 5.11$
Central	$15.86 \pm 2.85$	$15.82 \pm 2.89$	$15.79 \pm 2.89$	$16.00 \pm 2.81$	$15.99 \pm 2.87$	$15.81 \pm 2.87$
South	$20.35 \pm 4.69$	$20.38 \pm 4.72$	$20.24 \pm 4.80$	$20.60 \pm 4.55$	$20.54 \pm 4.66$	$20.35 \pm 4.69$
Total	$19.78 \pm 5.00$	$19.86 \pm 5.04$	$19.65 \pm 5.07$	$19.91 \pm 4.98$	$19.86 \pm 4.98$	$19.76 \pm 5.04$
Participants with event [ $n$ (%)]^a	8,632 (11.1%)	12,643 (16.6%)	7,266 (9.8%)	13,055 (18.7%)	20,541 (34.5%)	9,898 (13.0%)
Follow-up period (y)	$3.5 \pm 2.3$	$3.3 \pm 2.2$	$3.4 \pm 2.2$	$3.0 \pm 2.0$	$3.1 \pm 2.1$	$3.4 \pm 2.3$
Incidence rate (per 1,000 person-years)^b
North	34.23	49.74	23.22	55.93	123.12	37.94
Central	32.28	52.16	36.16	63.31	88.09	40.73
South	23.11	49.46	44.32	55.25	95.31	36.39
Total	31.95	50.01	28.89	56.81	112.77	38.07

Note: BP, blood pressure; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; MetS, metabolic syndrome; ${NO}_{2}$ , nitrogen dioxide; ${PM}_{2.5}$ , fine particulate matter (PM with an aerodynamic diameter of $less than or equal to 2.5 micrometers$ ); SD, standard deviation; TG, triglyceride.

^{^a}

Event referred to occurrence of MetS and components. For cohort without abdominal obesity, event meant having a waist circumference of $greater than or equal to 90 centimeters$ in men and $greater than or equal to 80 centimeters$ in women. For cohort with normal TG, event meant having a TG level of $greater than or equal to 150 milligrams per deciliter$ or receiving drug treatment for hypertriglyceridemia. For cohort with normal HDL-C, event meant having an HDL-C level of $less than 40 milligrams per deciliter$ ( $1.0 millimole per liter$ ) in males and $less than 50 milligrams per deciliter$ ( $1.3 millimoles per liter$ ) in females or receiving drug treatment for decreased HDL-C. For cohort with normal BP, event meant having a systolic BP level of $greater than or equal to 130$ or diastolic BP level of $greater than or equal to 85 millimeters of mercury$ or receiving drug treatment for hypertension. For, cohort with normal FBG, event meant having an FBG level of $greater than or equal to 100 milligrams per deciliter$ or receiving drug treatment for hyperglycemia. For cohort without MetS, event meant the presence of any three or more of the above components.

^{^b}

Incidence rate was calculated by dividing the number of events by total per 1,000 person-years for each cohort.