Table 1.

Univariable linear regression of the renal function.

	eGFR (ml/min/1.73 m 2 )
	B	p-values
Demographic characteristics
Female (ref: male)	2.64	***
Age (year)	−1.07	***
Race (ref: Mexican American)
Other Hispanic	−6.86	***
Non-Hispanic white	−15.36	***
Non-Hispanic black	−4.24	**
Other Race—including multi-racial	−5.43	***
Weight (kg)	−0.21	***
Height (cm)	−0.20	***
BMI (kg/m 2 )	−0.64	***
Marital status (ref: Married or living with partner)
Never married	12.55	***
Widowed, divorced, or separated	−11.51	***
Renal function
Blood urea nitrogen (mmol/L)	−7.76	***
Creatinine, refrigerated serum (umol/L)	−0.40	***
Uric acid (umol/L)	−0.10	***
Albumin creatinine ratio (mg/g)	−0.01	***
Metabolites of nicotine
Serum cotinine (ng/mL)	−0.02	***
Serum hydrocotinine (ng/mL)	−0.05	***
Sleep quality
Sleep duration on weekdays (h)	−0.11	0.60
How often do you snore? (ref: never)
Rarely−1–2 nights a week	−2.51	*
Occasionally−3–4 nights a week	−7.91	***
Frequently−5 or more nights a week	−8.60	***
How often do you snort or stop breathing (ref: never)
Rarely−1–2 nights a week	−2.66	*
Occasionally−3–4 nights a week	−6.78	***
Frequently−5 or more nights a week	−10.90	***
Smoking status
Age started smoking cigarettes regularly	−0.23	**
Do you now smoke cigarettes? (ref: Every day)
Some days	0.93	0.63
Not at all	−12.41	***
How soon after waking do you smoke (ref: Within 5 min)
6 ~ 30 min	−4.95	*
≥30 min	−1.81	0.40
# days smoked cigarettes during past 30 days	−0.42	***
Average # cigarettes/day during past 30 days	−0.21	*
Tried to quit smoking	0.78	0.60
Comorbidities
High blood pressure	−21.40	***
High cholesterol	−17.85	***
Diabetes (ref: Yes)
No	22.64	***
Borderline	10.27	***
Failing kidneys	−37.57	***
Anemia	−7.14	***
Congestive heart failure	−28.80	***
Coronary heart disease	−23.38	***
Stroke	−21.78	***
Chronic obstructive pulmonary disease	−16.74	***
Malignancy	−20.38	***

^*p < 0.05,

^**p < 0.01,

^***p < 0.001. Ref, reference group.