Smoking tobacco is associated with renal hyperfiltration

Figures & data

Table 1. Baseline characteristics of participants in the first cohort, stratified for tobacco status.

Variable	Nontobacco users	Smokers	p-value (nontobacco users vs smokers)	Snus users	p-value (nontobacco users vs snus users)	p-value (smokers vs snus users)
n	699	147		103
Sex (M/F)	467/232	92/55	0.375	102/1	<0.001	<.001
Age at sample donation (years)	59.2 (50.0; 60.1)	58.8 (50.1; 60.0)	0.434	50.2 (43.5; 59.7)	<0.001	<.001
Age men (years)	53.9 (49.9; 60.0)	50.2 (49.9; 60.0)	0.759	50.1 (43.4; 59.7)	0.001	0.025
Age women (years)	60.0 (52.8; 64.8)	59.8 (52.5; 60.2)	0.106	N/A	N/A	N/A
BMI^a	25.5 (23.6; 27.8)	24.7 (23.0; 27.4)	.019	25.7 (22.9; 27.8)	0.727	0.198
Diabetes (%)^b	5.1	6.6	0.663	4.3	0.938	0.668
SBT^c	133.2 (122.5;144.9)	129.6 (121.4;140.4)	0.002	131.4 (122.5;140.4)	0.042	0.482
eGFRcreatinine (ml/min/1.73m^2)
all	88.6 (82.3; 95.6)	92.0 (86.1; 98.5)	<.001	91.3 (86.4; 99.0)	<.001	0.847
men	90.2 (83.8; 97.1)	93.1 (86.2; 99.9)	0.012	91.3 (86.4; 99.0)	0.031	0.707
women	85.9 (79.5; 92.8)	91.1 (85.4; 97.8)	0.001	95.26	N/A	N/A
eGFRcystatin C (ml/min/1.73m^2)
all	82.0 (72.3; 92.2)	79.0 (70.2; 87.3)	0.052	86.2 (77.9; 98.9)	0.003	<0.001
men	82.3 (73.2; 92.5)	79.6 (71.8; 88.4)	0.247	86.2 (77.9; 99.0)	0.014	0.004
women	80.14 (70.9; 90.5)	78.1 (68.7; 86.2)	0.121	94.51	N/A	N/A

Medians (25th to 75th percentiles) for continuous variables Percent/proportions for noncontinuous variables. P-values <0.05 are shown in bold. N/A = not applicable. ^aBMI = body mass index (kg/m²); ^bDiabetes defined as fasting plasma glucose ≥7.0 mmol/L and⁄or post-load plasma glucose ≥ 11.0 mmol/L (12.2 mmol/L if capillary); ^cSBT = systolic blood pressure (mm Hg).

Table 2. Baseline characteristics of participants in the second cohort, stratified for tobacco status.

Variable	Nontobacco users	Smokers	p-value (nontobacco users vs smokers)	Snus users	p-value (nontobacco users vs snus users)	p-value (smokers vs snus users)
n	716	170		109
Sex (M/F)	377/339	92/78	0.796	104/5	N/A	N/A
Age at sample donation(years)	59.8 (50.1; 60.2)	50.8 (49.9; 60.1)	0.001	50.2 (40.3; 60.0)	<0.001	0.039
Age men	59.4 (50.0; 60.0)	50.3 (49.8; 60.0)	0.078	50.3 (40.3; 60.0)	0.011	0.428
Age women	59.9 (50.4; 65.5)	56.1 (50.0; 60.3)	0.005	N/A	N/A	N/A
BMI^a	25.7 (23.6; 28.1)	24.6 (22.8; 27.5)	0.005	26.5 (24.1; 28.8)	0.021	<0.001
Diabetes (%)^b	4.1	3.8	1.00	9.1	0.066	0.173
SBT^c	131.1 (122.6; 146.9)	127.4 (118.2; 140.1)	0.004	131.0(122.6; 143.4)	0.652	0.078
eGFR creatinine (ml/min/1.73m^2)
all	80.0 (73.4; 86.7)	85.6 (78.1; 93.5)	<0.001	83.2 (77.2; 89.1)	0.001	0.133
men	81.2 (75.2; 87.5)	87.3 (79.6; 96.3)	<0.001	83.3 (77.2; 89.1)	0.057	0.005
women	78.5 (71.2; 84.8)	82.7 (74.1; 90.0)	0.008	78.8(67.8; 89.5)	N/A	N/A
eGFR cystatin C (ml/min/1.73m^2)
all	90.9 (80.6; 102.0)	89.3 (79.0; 101.9)	0.598	92.5 (83.5; 101.7)	0.289	0.199
men	90.9 (82.1; 101.7)	89.2 (77.7; 99.1)	0.147	92.3 (83.4; 101.4)	0.547	0.101
women	90.8 (77.9; 103.1)	90.3 (80.1; 106.2)	0.455	98.5 (89.5; 107.9)	N/A	N/A

Medians (25th to 75th percentiles) for continuous variables. Percent/Proportions for noncontinuous variables. P-values <0.05 are shown in bold. N/A = not applicable. ^aBMI = body mass index (kg/m²); ^bDiabetes defined as fasting plasma glucose ≥7.0 mmol/L and⁄or postload plasma glucose ≥ 11.0 mmol/L (12.2 mmol/L if capillary); ^cSBT = systolic blood pressure (mm Hg).

Table 3. Associations of smoking with eGFR_creatinine and eGFR_{cystatin C} stratified for sex.

	eGFRcreatinine							eGFRcystatin C
Predictor variable	B	SE B	Beta/ β	sr	P	R^2	ΔR^2	B	SE B	Beta/ β	sr	P	R^2	ΔR^2
Men
Step 1						0.25	0.25						0.13	0.13
Constant	3.04	0.19			<0.001			2.29	0.20			<0.001
Smoking	0.37	0.07	0.14	0.14	<0.001			−0.13	0.08	−0.05	−0.05	0.09
Age	−0.06	<0.01	−0.47	−0.47	<0.001			−0.04	<0.01	−0.36	−0.35	<0.001
Step 2						0.25	<0.01						0.13	0.01
Constant	3.43	0.31			<0.001			2.44	0.32			<0.001
Smoking	0.37	0.08	0.14	0.14	<0.001			−0.15	0.08	−0.06	−0.06	0.06
Age	−0.06	<0.01	−0.45	−0.43	<0.001			−0.04	<0.01	−0.34	−0.33	<0.001
BMI^a	< −0.01	0.01	−0.01	−0.01	0.641			0.01	0.01	0.02	0.02	0.46
Diabetes^b	<0.01	<0.01	0.01	0.01	0.705			<0.01	<0.01	−0.05	−0.05	0.09
SBT^c	< −0.01	<0.01	−0.05	−0.05	0.111			<0.01	<0.01	−0.05	−0.05	0.13
Cohort^d	< −0.01	0.06	< −0.01	<-0.01	0.946			0.02	0.06	0.01	0.01	0.80
Women
Step 1						0.23	0.23						0.20	0.20
Constant	3.25	0.32			<.001			3.16	0.33			<0.001
Smoking	0.16	0.12	0.06	0.06	0.163			−0.14	0.12	−0.05	−.05	0.258
Age	−0.06	0.01	−0.47	−0.47	<.001			−0.05	0.01	−0.45	−.45	<0.001
Step 2						0.28	0.05						0.34	0.14
Constant	2.73	0.40			<.001			2.22	0.38			<0.001
Smoking	0.26	0.12	0.10	0.10	0.026			0.04	0.11	0.01	0.01	0.742
Age	−0.05	0.01	−0.45	−0.36	<0.001			−0.06	0.01	−0.49	−0.39	<0.001
BMI^a	−0.06	0.01	−0.68	−0.20	<0.001			−0.11	0.01	−1.20	−0.35	<0.001
Diabetes^b	<0.01	<0.01	−0.69	−0.20	<0.001			<0.01	<0.01	−0.97	−0.29	<0.001
SBT^c	0.02	<0.01	0.33	0.19	<0.001			0.03	<0.01	0.58	0.34	<0.001
Cohort^d	−0.08	0.11	−0.04	−0.03	0.473			0.16	0.11	0.08	0.07	0.126

SE B = standard error unstandardized coefficients B; β = standardized coefficients Beta; sr = semipartial correlation coefficient; ΔR² = R squared change; ^aBMI = body mass index (kg/m²); ^bDiabetes defined as fasting plasma glucose ≥7.0 mmol/L and⁄or postload plasma glucose ≥ 11.0 mmol/L (12.2 mmol/L if capillary); ^cSBT = systolic blood pressure (mm Hg); ^d Origin from first or second cohort. P-values <0.05 are shown in bold.

Data availability statement

Aggregate data are included in the manuscript and its Supporting Information files.

The data that support the findings of this study are available on request from the Northern Sweden Health and Disease Study Biobank. To request data, interested researchers must complete a formal application (available at https://www.umu.se/en/biobankresearch-unit/research/access-to-samples-anddata/access-to-nsdd/) and submit it to The Biobank Research Unit at Umeå University (contact via [email protected]). Individual data are not publicly available due to containing information that could compromise the privacy of research participants.