Association between Cigarette Consumption and Proteinuria in Healthy Japanese Men and Women from an Occupational Population

Burden of Proteinuria and Risk Factors of Chronic Kidney Disease among Adult Population in Urban Puducherry, India

INTRODUCTION

In the recent times, Chronic Kidney Diseases (CKDs) are emerging as a serious problem all over the world along with diabetes mellitus and hypertension. The presence of proteinuria is considered as an indicator of increased risk of progressive kidney diseases.

AIM

To determine the prevalence of proteinuria among an adult population of a tertiary care institute of Puducherry, India.

MATERIALS AND METHODS

A cross-sectional study was carried out in the field practice areas of an urban health centre of a tertiary care institute, in Puducherry, India. A total of 215 study respondents were selected by systematic random sampling. All adults aged above 18 years who were residing for at least a year in Puducherry were included in the study. The study period was from July 2015 to October 2015. All the categorical variables were described as proportions. Chi square test was done to compare between two proportions. Univariate analysis was done to estimate the Odds Ratio (OR) with 95% CI.

RESULTS

The mean age of the study participants was 38.5±12.8 years. Majority, 145 (67.4%) of the study participants were females. The prevalence of proteinuria was found to be 9.3%. While 4.7% and 11.2% of participants used tobacco and alcohol respectively, 13.5% and 27.9% had diabetes mellitus and hypertension respectively. Elderly age, diabetes mellitus and hypertension were found to be statistically significant predictors for proteinuria.

CONCLUSION

The prevalence of proteinuria was high in our study population (9.3%) and hypertension and diabetes mellitus were also found to be risk factors for CKD. Routine screening among the general population for proteinuria in community-based settings might be an effective step to bring down the rate of progression of CKD.

Distribution of and factors contributing to chronic kidney disease in a middle-aged working population

OBJECTIVES

To clarify the distribution of chronic kidney disease (CKD) and the factors contributing to its development and progression in middle-aged Japanese workers/employees.

METHODS

This was a retrospective study involving 3,964 men and 2,698 women aged 35-64 years in 2009 who had been followed-up until 2003. Data on proteinuria determined with a dipstick and glomerular filtration rate estimated from serum creatinine concentration (eGFR) were collected in the annual health check-ups.

RESULTS

Proteinuria was detected in 2.9 and 1.1 % of the men and women, respectively, and total CKD was detected in 16.0 and 16.1 % of the men and women respectively. Moderate or severe CKD associated a high risk of cardiovascular diseases and end-stage kidney disease was found mostly in the male subjects [2.0 (men) vs. 0.6 % (women)]. High-risk CKD was found in 3.3 % of the men aged 55-64 years. A body mass index (BMI) of ≥30, hypertension, diabetes mellitus (DM), current smoking and some job types were independently related to the development of proteinuria, while age, BMI, hypertriglyceridemia, and job types were related to total CKD. The development of high-risk CKD was related to preceding mild CKD signs of reduced eGFR and proteinuria as well as to hypertension, DM, smoking, and job type.

CONCLUSIONS

Chronic kidney disease was found in 16 % of middle-aged workers with an equal prevalence in both sexes, while high-risk CKD was found mostly in men, of whom 3.3 % were aged 55-64 years. Obesity, hypertension, DM, smoking and some job types were related to the development and progression of CKD.

The effects of continuing and discontinuing smoking on the development of chronic kidney disease (CKD) in the healthy middle-aged working population in Japan

OBJECTIVES

The strength of the association between smoking and the development of chronic kidney disease (CKD) in the healthy middle-aged working age population has not been established.

METHODS

This was a retrospective 6-year observational study involving 4,121 male and 2,877 female workers who were free of primary kidney disease, diabetes mellitus, severe hypertension, and the signs and symptoms of CKD. Proteinuria was detected by a dipstick method, and glomerular filtration rate (GFR) was estimated by the equation of the Japan Society of Nephrology.

RESULTS

Sixty men (1.5 %) and 21 women (0.7 %) developed proteinuria over the 6 years of the study. Irrespective of sex, in comparison with non-smokers, those who continued smoking showed an odds ratio (OR) of 2.52 with a 95 % confidence interval (CI) of 1.50-4.25 for developing proteinuria while those who quit smoking showed an OR of 1.29 (95 % CI 0.48-3.42), following adjustment for confounders. Among the study population, 443 men (10.7 %) and 356 women (12.4 %) developed a GFR of <60 mL/min/1.73 m(2), corresponding to stage III CKD. Continuing smokers had a low OR (0.74, 95 % CI 0.60-0.90) for developing a low GFR, as well as a higher mean GFR than non-smokers. The reduction in GFR during the 6-year study period was not different between smokers and non-smokers, but it was larger in those who developed proteinuria than in those who did not, irrespective of smoking.

CONCLUSIONS

Continuing smokers showed a twofold or more higher risk of developing proteinuria. Discontinuation of smoking substantially reduced the risk. A longer observational period may be required to detect the smoking-induced risk of developing stage III CKD in the middle-aged working population.

Smoking and chronic kidney disease in healthy populations

The objective of this review is to explore the link between smoking and the development of chronic kidney disease (CKD) in generally healthy populations without pre-existing renal dysfunction such as diabetic nephropathy. Twenty-eight epidemiological studies concerning the renal effects of smoking in the general population were collected from the MEDLINE database and were reviewed for indications of proteinuria and/or the decline of glomerular filtration rate (GFR), and evaluated on the level of evidence and the quality of the study. Sixteen of the 28 studies were cross-sectional in design. Most articles had some weakness in scope, such as the 6 articles which did not fully exclude DM patients from the subjects, the 4 that did not consider the effects of ex-smoking, and the 3 that focused on only a small number of subjects. From these cases, it is difficult to draw firm conclusions. However, proteinuria or microalbuminuria was persistently high in current smokers; as much as 5-8% or 8-15% respectively, which was up to 2 to 3-times the rate of lifelong non-smokers. On the other hand, only 5 studies broader in scope detected any decline of GFR in smokers, while 9 other studies suggested a higher GFR in smokers than in non-smokers. Two good quality studies showed an even a significantly lower risk of a decreased GFR in smokers. These paradoxical CKD markers in smokers, i.e., a higher appearance of proteinuria with a higher GFR, could be a focus for further studies to reveal the underlying reasons for smoking-induced CKD. Workplaces may be an excellent place to study this subject since the long-term changes in renal function of smokers can be observed by collecting data in the annual health check-ups mandated at places of employment.

Cigarette smoking, proteinuria, and renal function in middle-aged Japanese men from an occupational population

OBJECTIVES

To clarify the renal effects of cigarette smoking in a middle-aged occupational population because the effects have previously been demonstrated mainly in community populations that included many elderly people who are thought to be vulnerable to such effects.

METHODS

In 990 middle-aged men recruited from a chemical plant, proteinuria was measured by a dipstick method and the glomerular filtration rate was estimated (eGFR) using a formula proposed by the Japanese Society of Nephrology.

RESULTS

Proteinuria was found in 4.6% of the current smokers and 1.5% of the never-smokers. It was found in 4.8% of the subjects having a Brinkman index (BI) of 400-599 and 6.3% of those having a BI of 600 or above. The odds ratio for proteinuria in them was 2.94 (CI: 1.01-8.55) and 3.61 (CI: 1.29-10.1), respectively, adjusting for possible confounders. The mean eGFR was higher in smokers than in nonsmokers throughout middle age up to 64 years. Normal but high eGFR was found in 6.7% of the current heavy smokers and subnormal eGFR in 5.7% of the largest cumulative cigarette consumers in contrast to 3.0% or less of the never-smokers. Proteinuria was found in 13.3% of the subjects showing subnormal eGFR, specifically in 16.7% of the smokers and 8.3% of the nonsmokers.

CONCLUSIONS

Smoking causes proteinuria in working middle-aged men. Smokers tend to have a high eGFR, but those with subnormal eGFR showed proteinuria most frequently. Whether the high eGFR in smokers will eventually decrease and cause proteinuria remains an important focus for further studies.

Prevalence and risk factors of undetected proteinuria in an elderly South-East Asian population

BACKGROUND

Urinalysis is not a standard component of health screening in the elderly population.

OBJECTIVE

We investigated the prevalence and risk factors of undetected renal disease as defined by proteinuria (PR) in an elderly South-East Asian population.

METHOD

There were 19,848 participants of age >or=65 years in National Kidney Foundation's Nationwide Screening programme at Singapore. Mean age was 70.6 +/- 5.3 years. After excluding the 1.1% who had pre-existing renal disease, 8.5% were identified to have previously undetected PR defined as >or=1+ protein on urine dipstick analysis. Multivariate regression revealed that male gender (OR = 1.2, reference category (Ref): female), known diabetes (odds ratio (OR) = 2.28; P < 0.0001), hypertension (OR = 1.62; P = 0.0001), presence of elevated blood pressure (BP) (>or=120/90 mmHg) on screening (OR = 1.38, 1.89, 3.45 for mild, moderate and severe BP, respectively, all P < 0.0001), elevated body mass index (BMI) (OR = 1.3 for BMI >or=23 vs BMI < 23 kg/m(2)), and smoking (OR = 1.2, ref: non-smokers) were significantly associated with PR. Finally, a progressive increase in OR for PR was observed with stepwise increase in age (years) (OR for 67-68.9: 1.2, P = 0.025; 69-72.9, 1.49, P = 0.49; >or=73: 1.56, P < 0.0001, Ref: 65-66.9 years).

CONCLUSION

We conclude that there is high prevalence of previously undetected proteinuria in elderly South-East Asians. Because proteinuria is a risk factor for cardiovascular disease, our findings support inclusion of urinalysis in routine health screening for this population.

Hypertension and kidney disease in Asia

PURPOSE OF REVIEW

Communicable diseases were traditionally the major cause of public health concern in Asian countries, most of which were less developed. With industrialization and associated lifestyle changes during the past few decades, however, noncommunicable diseases similar to those that affect Western societies have emerged in Asian countries. The purpose of the review was to examine recent evidence about the burden and factors associated with hypertension and chronic kidney disease (CKD) in Asian countries.

RECENT FINDINGS

Hypertension has become one of the leading causes of mortality in Asia. Although its prevalence continues to rise, it remains under-diagnosed and under-treated. CKD is becoming increasingly common mainly due to an increase in risk factors such as high blood pressure, diabetes, and obesity. Treatment of advanced CKD is overwhelmingly burdensome in a resource poor environment. Barriers to early detection of CKD in Asians include the fact that equations to estimate the glomerular filtration rate have not been validated in this population, and the uncertainty about appropriate glomerular filtration rate cutoff values to define CKD.

SUMMARY

Concerted efforts are needed to develop and implement cost-effective strategies for prevention and treatment of hypertension and CKD in Asian countries. More research is needed on these conditions in these populations.