The prevalence of chronic kidney disease (CKD) is increasing rapidly worldwide and is now recognized as a global public health problem [
CKD is matched the Wilson criteria for screening due to it is an important health problem; the disease natural history should be understood; a recognizable latent or early symptomatic stage; a test is easy to perform and interpret, acceptable, accurate, reliable, sensitive and specific; an accepted treatment recognized for the disease; treatment is more effective if started early; a policy on who should be treated; diagnosis and treatment are cost-effective; and case-finding should be a continuous process [
This cross-sectional study was conducted with a total of 2,766 male aged 65 years and over healthy occupational adults with agricultural and fishing professional fields voluntarily admitted to one teaching hospital in Northern Taiwan for an annual physical checkup between January 1, 2010 and December 31, 2010. All procedures were performed in accordance with the guidelines of our institutional ethics committee and adhered to the tenets of the Declaration of Helsinki. All patients’ information was anonymous.
The medical histories and measurements of the participants were obtained by well-trained nurses. Personal and family histories of hypertension, type 2 diabetes, cardiovascular diseases, and other chronic diseases were obtained by a structured health interview questionnaire. The study participants were asked to take off the shoes and any other belongings that could possibly add extra weight when they were weighed. Heights and weights were evaluated according to body mass index (BMI). Also the waist circumference was also measured at the level of the iliac processes and the umbilicus with a soft tape measure to estimate abdominal obesity. Blood pressures for each subject were measured twice in the sitting position with an interval of 15 minutes between the measurements, by means of standard sphygmomanometers of appropriate width, after a rest period for 30 minutes. Those who are taking antihypertensive therapy were considered to be known hypertension.
Fasting blood samples were drawn via venipuncture from study participants by clinical nurses. Overnight-fasting serum and plasma samples (from whole blood preserved with EDTA and NaF) were kept frozen (−20°C) until they are ready for analysis.
The estimated glomerular filtration rate (eGFR) was calculated using the MDRD equation, which was modified for data from Chinese CKD patients [
Metabolic syndrome was diagnosed according to NCEP ATP III criteria, that is, at least 3 of the following 5 parameters should be present: abdominal obesity (waist circumference > 90 cm for males), hypertension (SBP > 130 mm Hg and/or DBP > 85 mm Hg) or history of antihypertensive usage, hypertriglyceridemia (≥150 mg/dL) or presence of treatment for this disorder, low HDL-C (<40 mg/dL in males) or presence of treatment for this disorder, and high fasting plasma glucose (>100 mg/dL) or presence of diagnosis of type 2 diabetes [
For the health behavior factors, participants were asked in multiple choice formats to describe their intake of alcohol drinks. Bear, wine, and spirits were assessed separately. Current alcohol consumption was assessed by the question “How many cups, glasses, or drinks of these beverages do you usually drink a day or a month, and for how many years?” People who reported drinking were classified on the basis of the sum of their reported current consumption of all types of alcoholic beverages. We categorized daily ethanol intake in grams into 4 categories: nondrinkers, <20 g (mild), 20–70 g (moderate), and >70 g (heavy). Nondrinkers are defined as the people who explicitly recorded zero for current alcohol consumption of any alcoholic beverage and zero or blank for previous consumption. Heavy drinker is denied as daily alcohol intake >70 g [
Statistical analysis was performed using SPSS for Windows, (SPSS version 18.0; Chicago, IL, USA). The two-sample independent
As Figure
Age-specific prevalence of chronic kidney disease among elderly male fishing and agricultural population (
Table
Demographic characteristics of participants with and without chronic kidney disease (
Variables | General ( |
Age | Chronic kidney disease | |||||
---|---|---|---|---|---|---|---|---|
65–74 ( |
75–84 ( |
≥85 ( |
|
Yes ( |
No ( |
|
||
mean ± SD | mean ± SD | mean ± SD | mean ± SD | mean ± SD | mean ± SD | |||
Age (year) |
|
— | — | — | — |
|
|
<0.001 |
SBP (mm Hg) |
|
|
|
|
0.78 |
|
|
0.003 |
DBP (mm Hg) |
|
|
|
|
<0.001 |
|
|
0.67 |
BMI (kg/m²) |
|
|
|
|
0.78 |
|
|
0.64 |
Waist circumference (cm) |
|
|
|
|
0.03 |
|
|
0.02 |
Fasting blood glucose (mg/dL) |
|
|
|
|
<0.001 |
|
|
0.33 |
Triglycerides (mg/dL) |
|
|
|
|
<0.001 |
|
|
<0.001 |
Total cholesterol (mg/dL) |
|
|
|
|
0.90 |
|
|
0.72 |
HDL-C (mg/dL) |
|
|
|
|
0.03 |
|
|
<0.001 |
Uric acid (mg/dL) |
|
|
|
|
<0.001 |
|
|
<0.001 |
ALT (U/L) |
|
|
|
|
0.03 |
|
|
0.07 |
The relationship proportion of Chinese elderly male with CKD and individual components is shown in Table
The relationship between metabolic components and chronic kidney disease in the study participants (
65–74 yrs | 75–84 yrs | ≥85 yrs | Total |
|
|
---|---|---|---|---|---|
CKD |
CKD |
CKD |
CKD | ||
Metabolic components | |||||
Elevated blood pressure | 9.1 (7.3–10.9) | 19.4 (16.5–22.4) | 33.3 (25.2–41.4) | 14.8 (13.2–16.4) | 0.02 |
Central obesity | 11.0 (8.8–13.3) | 22.4 (18.7–26.1) | 32.9 (22.1–43.7) | 16.5 (14.5–18.5) | <0.001 |
Hyperglycemia | 12.3 (9.4–15.2) | 23.1 (18.5–27.7) | 31.9 (18.6–45.2) | 17.4 (14.9–19.9) | <0.001 |
Hypertriglyceridemia | 13.2 (10.1–16.3) | 27.2 (21.5–32.9) | 30.6 (15.6–45.7) | 18.6 (15.8–21.4) | <0.001 |
Low HDL-C | 16.0 (12.1–19.9) | 28.1 (22.2–34.0) | 35.7 (21.2–50.2) | 21.8 (18.5–25.1) | <0.001 |
Number of components of metabolic syndrome | |||||
None | 3.0 (0.8–5.2) | 5.9 (4.3–7.5) | 14.2 (11.2–17.2) | 8.5 (5.8–11.2) | |
One or two | 16.4 (10.4–22.4) | 15.1 (12.2–18.0) | 27.6 (22.6–32.6) | 11.1 (9.5–12.7) | <0.001 |
Three or more | 12.1 (1.0–23.2) | 27.2 (19.0–35.4) | 36.7 (23.2–50.2) | 20.3 (17.6–23.0) |
The effect of independent associated risk factors on CKD was examined using the multiple logistic regression model. As is depicted in Table
Multiple logistic regression on the risk factors associated with the chronic kidney disease among male elderly fishing and agricultural population (
Variables | CKD versus non-CKD | ||
---|---|---|---|
Odds ratio | 95% Confidence interval |
|
|
Model A | |||
Age (year) | 1.05 | 1.02–1.09 | 0.001 |
Smoking (yes versus no) | 0.87 | 0.66–1.18 | 0.32 |
(ex-smoker versus no) | 0.93 | 0.71–1.16 | 0.40 |
Alcohol drinking (<20 g/day versus no) | 1.03 | 0.81–1.39 | 0.26 |
(20–70 g/day versus no) | 0.88 | 0.69–1.12 | 0.14 |
(≥70 g/day versus no) | 1.20 | 0.92–1.47 | 0.07 |
Physical exercise (≥3 versus <3 times/week) | 0.79 | 0.62–1.04 | 0.06 |
Hyperuricemia (yes versus no) | 2.94 | 1.90–3.78 | <0.001 |
Central obesity (yes versus no) | 1.17 | 1.02–1.56 | 0.03 |
Elevated blood pressure (yes versus no) | 1.07 | 0.81–1.42 | 0.37 |
Hyperglycemia (yes versus no) | 1.23 | 1.11–1.67 | 0.01 |
Hypertriglyceridemia (yes versus no) | 1.25 | 1.08–1.66 | 0.01 |
Lower HDL-C (yes versus no) | 1.61 | 1.23–1.92 | 0.02 |
Obesity (yes versus no) | 1.05 | 0.87–1.31 | 0.28 |
Higher ALT (yes versus no) | 1.03 | 0.73–1.35 | 0.16 |
| |||
Model B | |||
Age (year) | 1.03 | 1.01–1.08 | 0.03 |
Smoking (yes versus no) | 0.89 | 0.63–1.21 | 0.37 |
(ex-smoker versus no) | 0.91 | 0.74–1.15 | 0.44 |
Alcohol drinking (<20 g/day versus no) | 1.01 | 0.78–1.43 | 0.35 |
(20–70 g/day versus no) | 0.86 | 0.65–1.14 | 0.19 |
(≥70 g/day versus no) | 1.11 | 0.84–1.40 | 0.09 |
Physical exercise (≥3 versus <3 times/week) | 0.84 | 0.65–1.03 | 0.11 |
Hyperuricemia (yes versus no) | 2.15 | 1.57–2.99 | <0.001 |
Metabolic components | |||
(One or two versus none) | 1.10 | 1.04–1.25 | 0.04 |
(Three or more versus none) | 2.12 | 1.86–2.78 | <0.001 |
Obesity (yes versus no) | 1.04 | 0.82–1.39 | 0.27 |
Higher ALT (yes versus no) | 1.04 | 0.71–1.32 | 0.19 |
All GFR estimating equations have some limitations due to diet or clinical conditions such as malnutrition and inflammation may also affect the applicability of the MDRD study equation for use with Asians, while the Cockcroft-Gault equation tends to overestimate the true GFR [
The most common types of morphological renal lesions observed in renal biopsies of obese patients are mainly focal and segmental glomerulosclerosis and glomerulomegaly [
Metabolic syndrome is more prevalent among males and the incidence increases with age [
Each component of metabolic syndrome, per se, may cause renal function damage [
In this study, hyperuricemia exhibited a significant high OR value and was therefore one of the strongest risk factors related to CKD. Other studies also showed that hyperuricemia is not only associated with CKD, but also independent of the presence of metabolic syndrome [
One of the major limitations to this study population is selected on a voluntary basis based on one area elderly population screened, which would potentially introduce selection bias. Voluntary bias can be defined as that comes from the fact that a particular sample can contain only those participants who are actually willing to participate in the study and who participate and find the topic particularly interesting and who are more likely to volunteer for that study, with the same being for those who are expected to be evaluated on a positive level [
The prevalence of CKD is related to older age, hyperuricemia, central obesity, hyperglycemia, hypertriglyceridemia, lower HDL-C, and metabolic syndrome in this study. Further studies are needed to elucidate the temporal sequence of events that typically lead to CKD among elderly population. In order to prevent the CKD, promoting this population with controlled obesity, uric acid, and health improvement for metabolic function is important.
The authors certify that all their affiliations with or financial involvement in, within the past 5 years and foreseeable future, any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript are completely disclosed (e.g., employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, royalties).
Chi-Mei Kuo, Hsi-Che Shen, and Yi-Chun Hu contributed equally to this study.