The Influence of Smoking on Renal Functions Among Apparently Healthy Smokers

Figures & data

Table 1 Baseline Characteristics Among Smokers and Non-Smokers

Groups items	Non-smokers N = 140	Smokers N = 140	P-value
Age (yrs)
Mean± SD	42±12.7	43.5±10.9	0.3
PLT
Mean± SD	276.9±76.2	265.6±83.8	0.2
WBCs
Mean± SD	7.3±1.9	7.2±2.2	0.7
RBCs
Mean± SD	4.5±0.7	4.4±1	0.9
Urea (mg/dL)
Mean± SD	26.5±7	31.1±6.9	0.000*
Creatinine (mg/dL)
Mean± SD	0.7±0.2	0.9±0.3	0.000*
Urinary albumin (mg/day)
Mean± SD	15.9±6.5	67.1±62.3	0.000*
Median	16.9	32
IQR	10.4	63.2
Serum cotinine (ng/mL)
Mean± SD	6.02±2.3	297.7±288.7	0.000*
Median	6	160
IQR	4	533.7
AST (mg/dL)
Mean± SD	22.2±5.6	22. 9±8.2	0.8
ALT (mg/dL)
Mean± SD	22±7.8	22.2±10.5	0.8
Na (mmol/l)
Mean± SD	139.2±3.6	139.5±3.9	0.5
K (mmol/l)
Mean± SD	4.1±0.4	4.2±0.4	0.3
HBA1C (mg/dL)
Mean± SD	4.3±0.7	4.5±0.9	0.06
Random blood sugar (mg/dL)
Mean± SD	130.3±12.4	132.7±9.2	0.07

Notes: *Indicates statistically significant difference, P-value <0.05.

Table 2 Kidney and Liver Function Parameters Among Active and Passive Smokers

Groups items	Active smokers N = 70	Passive smokers N = 70	P-value
Urea (mg/dL)
Mean± SD	31.5±6.9	30.6±7	0.5
Creatinine (mg/dL)
Mean± SD	0.9±0.3	0.9±0.2	0.7
Urinary albumin (mg/day)
Mean±SD	91.5±77.3	42.7±24.9	0.000*
Median	33	28.5
IQR	159.4	37
Serum cotinine (ng/mL)
Mean±SD	421.4±354	173.9±107.3	0.000*
Median	400	150
IQR	713	162.5
AST (mg/dL)
Mean± SD	30.3±9.3	28.2±6.9	0.1
ALT (mg/dL)
Mean± SD	23.1±12.2	21.3±8.4	0.3
Na (mmol/l)
Mean± SD	139.6±4.2	139.5±3.6	0.8
K (mmol/l)
Mean± SD	4.2±0.5	4.1±0.4	0.2

Notes: *Indicates statistically significant difference, P-value <0.05.

Table 3 Distribution of Urinary Albumin and Serum Cotinine Among Active Smokers

Groups items	Light smokers N = 33	Moderate smokers N = 11	Heavy smokers N = 26	P-value
Urinary albumin (mg/day)	24.9±6.2	78.6±66.9	181.4±17.9	0.000*
Mean±SD	P1 = 0.000*, P2 = 0.000*, P3 = 0.000*
Serum cotinine (ng/mL)	207.7±316.1	341±336.8	726.5±113	0.000*
Mean±SD	P1 = 0.1, P2 = 0.000*, P3 = 0.000*

Notes: P₁ (difference between light and moderate smokers), P₂ (difference between light and heavy smokers), P₃ (difference between moderate smokers and heavy smokers). * indicates statistically significant difference, P-value <0.05.

Table 4 Correlation Between Urinary Albumin and Some Parameters Among Active Smokers and Passive Smokers

Different parameters	Active smokers		Passive smokers
	r	p-value	r	P-value
Age (years)	0.02	0.8	0.2	0.1
Pack/year	0.9	0.000*	------	------
Smoking index	0.9	0.000*	-------	--------
Smoking duration	0.4	0.000*	0.4	0.001*
Serum cotinine (ng/mL)	0.6	0.000*	0.4	0.000*
Serum creatinine (mg/dL)	0.04	0.7	0.1	0.1
FVC	−0.2	0.03*	0.3	0.005*
FEV1	−0.3	0.008*	0.1	0.2
FEV1\FVC	0.1	0.2	0.2	0.06

Note: *Indicates statistically significant difference, P-value <0.05.

Table 5 Multiple Comparisons of Spirometric – Indices Between Active Smokers, Passive Smokers and Control Groups

Spirometric indices		Non-smokers	Active smokers	Passive smokers
FVC	Mean±SD	86.8±3.1	82.1±6.4	83.3±4.8
	P-value	P1 = 0.000*, P2 = 0.000*, P3 = 0.09
FEV1	Mean±SD	85.8±3.9	80.5±7. 2	82.9±5.5
	P-value	P1 = 0.000*, P2 = 0.000*, P3 = 0.007*
FEV1\FVC	Mean±SD	85.4±3.6	78.8.9±6.2	82.4±6.6
	P-value	P1 = 0.000*, P2 = 0.000*, P3 = 0.000*

Notes: P₁ (difference between non-smokers and passive smokers), P₂ (difference between non-smokers and active smokers), P₃ (difference between active smokers and passive smokers). *Indicates statistically significant difference, P-value <0.05.

Table 6 Determinants of Microalbuminuria Among Studied Group

Risk factors	OR (95% CI)	P-value
Smoking status (ref non-smoker)
-Passive smoker	23.5 (6.4–86)	0.000*
-Active smoker	60.5 (15–243)	0.000*
Age	1.04 (1.01–1.1)	0.001*
Serum cotinine (ng/mL)	1.003 (1.001–1.005	0.01*

Note: *Indicates statistically significant difference, P-value <0.05.

Figure 1 Correlation between urinary albumin (mg/day) and pack/year among active smokers. There was a statistically significant moderate positive correlations between the pack/year and, level of urinary albumin (r = 0.9 p<0.05) among studied participants.