| Objective Recently increased epidemiological investigations and clinical data have showed that serum homocysteine(Hcy) levels are 3 to 5 times higher than normal, or even more than 100μmol/L, in the end-stage renal disease(ESRD) patients.In those patients, Hcy levels could not decrease to the normal even after hemodialysis and renal transplantation. Serum Hcy levels increase with glomerular filtration rate(GFR) decrease. Therefore, it was speculated that high homocysteine(h Hcys) may be a key pathological factor in the progression of ESRD. Generally, serum Hcy levels in adults change from 5 to 15μmol/L. We questioned that whether this standard is also suitable for healthy elderly people. In addition, whether serum Hcy levels have a significant impact on renal function in healthy elderly people? If so, is this effect independent of age? At present, little research has been found about those questions.Therefore, we measured the serum Hcy levels in some of male elderly people from Tianjin medical university general hospital medical center from January to December in 2014. The relationship between Hcy and GFR was analyzed. We studied the influence of serum Hcy levels on renal function damage in those subjects.Method A cross sectional study was conducted based on the data collected from medical center in 2014 in Tianjin medical university general hospital. 500 subjects aged 65 to 90 were randomly selected with no smoking and alcohol consumption less than 1-2 times/month. Some of them were excluded, if they had history of serve ardio-cerebrovascular disease, hypertension, diabetes mellitus, chronic kidney disease,taking drugs with renal toxicity recently and incomplete documentation. Finally total349 subjects were enrolled in the study. Serum Hcy levels were measured by direct chemiluminescence.We analyzed the average serum Hcy concentration and GFR level from these subjects. h Hcys is defined as the level above 16μmol/L. According to the chronic kidney disease(CKD) stages from American kidney foundation, GFR less than 60 ml∕(min·1.73m2) is used as criterion for moderate kidney damage. All subjects were divided into h Hcys group(121 cases) or control group(228 cases). The differences of several factors, such as serum Hcy, age, height, weight, blood pressure, blood sugar,blood lipid, uric acid, urea, creatinine, GFR and the prevalence of moderate kidney damage, were compared between two groups. The correlations between GFR and Hcy,uric acid were analyzed with Pearson correlation analysis. According to the serum Hcy levels quarterback spacing, all subjects were divided into four groups. The relationship between serum Hcy levels and the risk of moderate kidney damage was analyzed by logistic regression analysis.Result The average serum Hcy level was 15.66umol/L and the prevalence of h Hcys was 34.67%(121/349) in these subjects. The average GFR level was 67.83 ml ∕(min·1.73m2) and the prevalence of moderate kidney damage was 36.68%(128/349).There were statistically significant differences in serum Hcy [(21.56±5.96) vs(12.53±2.20)μmol/L], uric acid [(353±75) vs(320±69)μmol/L)], creatinine [(93±18)vs(83±12)μmol/L)], the prevalence of moderate kidney damage(49.59% vs 29.82%)and the GFR levels [(62.22±17.25) vs(70.81±17.93)ml/(min·1.73m2)] between h Hcys group and control group. GFR was used as a main index to evaluate renal function.Correlation analysis demonstrated that GFR levels were negatively correlated with Hcy(r=-0.196,P<0.001), age(r=-0.661,P<0.001), but not correlated with uric acid(r=-0.074,P= 0.170). According to serum Hcy levels quarterback spacing, all subjects were divided into four groups. Logistic analysis showed that higher serum Hcy levels significantly increased the risk of moderate kidney damage. Compared with the first group as reference, the odd ratio from the second to the forth group was1.882、1.789、3.955 respectively. There was statistical difference between first group and fourth group(P<0.001). One-Way ANOVA showed that three factors including Hcy(F=273.486,P<0.001)、age(F=9.092,P<0.001) and uric acid(F=5.484,P=0.001) were risk factors of renal function. Backward stepwise regression method was used to corrected age and uric acid factor. The result showed that age(P<0.001)but not uric acid(P=0.084) had a significant impact on the risk of moderate kidney damage.Conclusion In this study, we investigated the average level of serum Hcy and renal function in some males from 65 to 90 years old in Tianjin. We find that high serum Hcy levels and low GFR levels are prevalent in general, and the prevalence of h Hcys and moderate kidney damage are both as high as one-third among the subject. There are lower GFR levels and higher prevalence of moderate kidney damage in h Hcys elderly people compared with no- h Hcys ones. With serum Hcy levels increasing,GFR levels decreased significantly and the risk of moderate kidney damage increased obviously. This effect of Hcy levels on renal function damage is independent of age.We suggest that high level of serum Hcy may be a risk factor for renal damage that should not be ignored in elderly people. |
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