Table 1.

Baseline characteristics of all cohort participants and the individuals who developed gastrointestinal cancers during the follow-up period in the Golestan Cohort Study.

Baseline characteristics	GI cancer cases ($N=962$) N (%) or $\text{mean}\pm \text{SD}$	Cohort Participants ($N=\mathrm{50,034}$) N (%) or $\text{mean}\pm \text{SD}$	$p$-Value
Age (y)	$59.0\pm 9.1$	$52.0\pm 8.9$	$<0.001$
Gender			$<0.001$
Male	579 (60.1)	21,228 (42.4)
Female	383 (39.8)	28,806 (57.5)
Ethnicity			$<0.001$
Turkman	777 (80.7)	37,245 (74.4)
Non-Turkman	185 (19.2)	12,789 (25.5)
Residence			$<0.001$
Rural	815 (84.7)	40,002 (79.9)
Urban	147 (15.2)	10,032 (20.0)
Residence districts			$<0.001$
Maraveh-tappeh	111 (11.5)	3,448 (6.8)
Kalaleh	233 (24.2)	10,731 (21.4)
Gonbad	555 (57.6)	30,298 (60.5)
Aq-qala	63 (6.5)	5,557 (11.1)
Wealth scorea			$<0.001$
First quartile (lowest)	364 (37.8)	13,932 (27.8)
Second quartile	218 (22.6)	11,144 (22.2)
Third quartile	211 (21.9)	12,582 (25.1)
Fourth quartile (highest)	169 (17.5)	12,376 (24.7)
Smoking (pack-years)			$<0.001$
Never	723 (75.1)	41,378 (82.7)
Lowest tertile ($<5.7$)	73 (7.5)	2,893 (5.7)
Middle tertile (5.7–20)	70 (7.2)	2,993 (5.9)
Highest tertile ($>20$)	96 (9.9)	2,770 (5.5)
Opium consumption (nokhod-years)b			$<0.001$
Never	714 (74.2)	41,548 (83.0)
Lowest tertile ($\le 9$)	75 (7.8)	2,883 (5.7)
Middle tertile (9.1–46)	72 (7.4)	2,784 (5.5)
Highest tertile ($\ge 46.5$)	101 (10.5)	2,819 (5.6)
Regular alcohol drinking			0.375
Never	924 (96.0)	48,325 (96.5)
Ever	38 (3.9)	1,709 (3.4)

Note: GI, gastrointestinal; N, number.

^aWealth score was previously created using multiple correspondence analysis on the ownership of house, vehicle, and some home appliances.

^bNokhod is a local unit for opium consumption that equals $0.2\text{\hspace{0.17em}grams}$ of opium.