Genetic approaches in the clinical investigation of complex disorders: malnutrition, inflammation, and atherosclerosis (MIA) as a prototype

Aberrant inflammatory profile in acute but not recovered anorexia nervosa

Anorexia nervosa (AN) is a severe psychiatric disorder with high mortality and relapse rates. Even though changes in inflammatory markers and cytokines are known to accompany cachexia associated with somatic disorders such as cancer and chronic kidney disorder, studies on inflammatory markers in AN are rare and typically include few individuals. Here, we utilize an Olink Proteomics inflammatory panel to explore the concentrations of 92 preselected inflammation-related proteins in plasma samples from women with active AN (N = 113), recovered from AN (AN-REC, N = 113), and normal weight healthy controls (N = 114). After correction for multiple testing, twenty-five proteins differed significantly between the AN group and controls (lower levels: ADA, CCL19, CD40, CD5, CD8A, CSF1, CXCL1, CXCL5, HGF, IL10RB, IL12B, 1L18R1, LAP TGFß1, MCP3, OSM, TGFα, TNFRSF9, TNFS14 and TRANCE; higher levels: CCL11, CCL25, CST5, DNER, LIFR and OPG). Although more than half of these differences (N = 15) were present in the comparison between AN and AN-REC, no significant differences were seen between AN-REC and controls. Furthermore, twenty-five proteins correlated positively with BMI (ADA, AXIN1, CASP8, CD5, CD40, CSF1, CXCL1, CXCL5, EN-RAGE, HGF, IL6, IL10RB, IL12B, IL18, IL18R1, LAP TGFß1, OSM, SIRT2, STAMBP, TGFα, TNFRSF9, TNFS14, TRANCE, TRAIL and VEGFA) and four proteins correlated negatively with BMI (CCL11, CCL25, CCL28 and DNER). These results suggest that a dysregulated inflammatory status is associated with AN, but, importantly, seem to be confined to the acute illness state.

Inflammation in Peritoneal Dialysis: A Latin-American Perspective

Peritoneal dialysis (PD) patients present an extremely high mortality rate, but the mechanisms mediating the increased risk of mortality observed in this group of patients are still largely unknown, which limits the perspective of effective therapeutic strategies. The leading hypothesis that tries to explain this high mortality risk is that PD patients are exposed to a number of traditional risk factors for cardiovascular disease (CVD) already at the onset of their chronic kidney disease (CKD), since many of these risk factors are common to both CVD and CKD. Of particular importance, chronic inflammation recently emerged as an important novel risk factor related to multiple complications of CKD. There are many stimuli of the inflammatory response in CKD patients, such as fluid overload, decreased cytokine clearance, presence of uremia-modified proteins, presence of chronic infections, metabolic disturbances (including hyperglycemia), obesity. Many of these factors are related to PD. Latin America has made some progress in economic issues; however, a large portion of the population is still living in poverty, in poor sanitary conditions, and with many health-related issues, such as an increasing elderly population, low birth weights, and increasingly high energy intake in the adult population, which, in combination with changes in lifestyle, has provoked an increase in the prevalence of obesity, diabetes, and CVD. Therefore, in Latin America, there seems to be a peculiar situation combining high prevalence of low education level, poor sanitary conditions, and poverty with increases in obesity, diabetes, and sedentary lifestyle. Since inflammation and mortality risk are intimately related to both sides of those health issues, in this review we aim to analyze the peculiarities of inflammation and mortality risk in the Latin-American PD population.

Lower body mass index is not of more benefit for diabetic complications

AIMS/INTRODUCTION

To investigate the relationship between different body mass index (BMI) levels and vascular complications in type 2 diabetes mellitus patients.

MATERIALS AND METHODS

Data were collected from 3,224 individuals with type 2 diabetes mellitus (male/female: 1,635/1,589; age 61.31 ± 11.45 years), using a retrospective case study design. The association of BMI quintiles and diabetes mellitus vascular complications was assessed using multiple logistic regression models adjusting for age, sex, diabetes duration, smoking status, drinking and other confounders, using those with the lowest quintile of BMI as the reference group.

RESULTS

With increasing BMI, the detection rate of diabetic peripheral neuropathy and peripheral arterial disease initially decreased and then it increased, whereas the detection rate of diabetic kidney disease and carotid atherosclerotic plaques showed an upward trend; however, diabetic retinopathy was irregular. The odds ratios of diabetic peripheral neuropathy decreased as BMI increased from the 21st percentile to the 80th percentile initially, and increased when BMI was in >80th percentile. The same result was shown in peripheral arterial disease. BMI >80th percentile showed a 1.426-fold risk of diabetic kidney disease and a 1.336 -fold risk of carotid atherosclerotic plaque.

CONCLUSIONS

In patients with type 2 diabetes mellitus, the relationship between different BMIs and vascular complications varies. A U-shaped relationship was observed between BMI and diabetic peripheral neuropathy, as well as BMI and peripheral arterial disease. BMI is positively correlated with diabetic kidney disease and carotid atherosclerotic plaque; however, it is not correlated with diabetic retinopathy.

Bidirectional association between ESRD dialysis and diabetes: National cohort study

Background

Diabetes is associated with development of end-stage renal disease (ESRD) dialysis, but it is not clear whether ESRD dialysis is a risk factor for new-onset diabetes (NODM).

Methods

Using the Taiwan National Health Insurance Research Database, we designed two cohort studies to determine the association between dialysis and diabetes. Analysis 1 estimated the hazard ratios (HR) of ESRD dialysis in 20,585 patients with type 2 diabetes (T2DM) and 82,340 gender- and age- matched controls without diabetes. Analysis 2 estimated the HRs of NODM in 18,489 ESRD patients undergoing dialysis and 73,956 gender- and age- matched controls without ESRD dialysis. The follow-up period was from 2000 to date of endpoint, the date of death, or December 31, 2008. Cox proportional models were used to estimate the relative hazards.

Results

In analysis 1, the incidence of ESRD dialysis was higher in the T2DM cohort than in the non-diabetes cohort (6.78 vs. 0.61 per 1,000 person-years; HR: 7.97; 95%CI: 7.05–8.00). In analysis 2, the incidence of NODM was higher in the ESRD dialysis cohort than in the without-ESRD dialysis cohort (22.84 vs. 13.99 per 1,000 person-years; HR: 1.40; 95% CI: 1.34–1.47).

Conclusions

ESRD dialysis and diabetes were bidirectionally associated. The relationship between T2DM and incident ESRD dialysis was much stronger than between ESRD dialysis and NODM. Further studies are needed to determine the mechanism of ESRD dialysis-related NODM.

Plasma visfatin/nicotinamide phosphoribosyltransferase (visfatin/NAMPT) concentration is not related to kidney function in elderly subjects

BACKGROUND

Studies assessing plasma visfatin/nicotinamide phosphoribosyltransferase (NAMPT) concentrations in chronic kidney disease with the ELISA method are restricted mainly to subjects with end-stage kidney disease. Therefore, little is known about to what extent glomerular filtration rate (GFR) affects the plasma levels of visfatin/NAMPT. The aim of this study was to assess the relations between circulating visfatin/NAMPT levels and estimated GFR (eGFR), independently of potential confounders such as inflammation, nutritional status, and insulin resistance in the elderly population.

METHODS

The analysis included 3023 elderly subjects (1076 with impaired kidney excretory function - eGFR <60 mL/min/1.73 m2) who were participants of the PolSenior study. Serum insulin, glucose, creatinine, C-reactive protein, interleukin-6, and plasma visfatin/NAMPT concentrations were measured by a highly specific ELISA method. Insulin resistance was assessed on the basis of homeostasis model assessment for insulin resistance, and kidney excretory function was assessed using the full MDRD formula.

RESULTS

Similar plasma visfatin/NAMPT levels were found in subjects with eGFR ≥60 and <60 mL/min/1.73 m2 (0.96 ng/mL in both groups), and even in those subjects with eGFR 15-30 mL/min/1.73 m2 (0.83 ng/mL). Additionally, there was no association between plasma visfatin/NAMPT concentrations and eGFR values in models of regression analysis including confounding factors.

CONCLUSIONS

The results of our study suggest that plasma visfatin/NAMPT levels are not affected by impaired kidney excretory function in elderly subjects.

Selection of genetic and phenotypic features associated with inflammatory status of patients on dialysis using relaxed linear separability method

Identification of risk factors in patients with a particular disease can be analyzed in clinical data sets by using feature selection procedures of pattern recognition and data mining methods. The applicability of the relaxed linear separability (RLS) method of feature subset selection was checked for high-dimensional and mixed type (genetic and phenotypic) clinical data of patients with end-stage renal disease. The RLS method allowed for substantial reduction of the dimensionality through omitting redundant features while maintaining the linear separability of data sets of patients with high and low levels of an inflammatory biomarker. The synergy between genetic and phenotypic features in differentiation between these two subgroups was demonstrated.

Cardio-renal cachexia syndromes (CRCS): pathophysiological foundations of a vicious pathological circle

Cardio-renal syndromes (CRS) are defined as disorders of the heart and kidney whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. CRS have been classified into five categories, where types 2 and 4 represent respectively chronic cardio-renal and chronic reno-cardiac syndromes. In these conditions, the chronic disorder of either the heart or kidney has been shown to induce some degree of cachexia. At the same time, cachexia has been proposed as a possible mechanism contributing to the worsening of such pathological organ cross talk. Common pathogenetic mechanisms underlie body wasting in cachectic states of different chronic heart and kidney diseases. In these circumstances, a vicious circle could arise, in which cachexia associated with either heart failure or chronic kidney disease may contribute to further damage of the other organ. In chronic CRS, activation of the immune and neuroendocrine systems contributes to the genesis of cachexia, which in turn can negatively affect the heart and kidney function. In patients with cardiac sustained activation of the immune and neuroendocrine systems and oxidative stress, renal vascular resistance can increase and therefore impair renal perfusion, leading to worsening kidney function. Similarly, in renal cachexia, increased levels of pro-inflammatory cytokines can cause progressive left ventricular systolic dysfunction, myocardial cell death, endothelial dysfunction and increased myocardial fibrosis, with consequent impairment of the chronic reno-cardiac syndrome type 4. Thus, we speculate that the occurrence of different types of chronic CRS could represent a fundamental step in the genesis of cachexia, being renal and cardiac dysfunction closely related to the occurrence of systemic disorders leading to a final common pathway. Therefore, the heart and kidney and cachexia represent a triad causing a vicious circle that increases mortality and morbidity: In such circumstances, we may plausibly talk about cardio-renal cachexia syndrome. Complex interrelations may explain the transition from CRS to cachexia and from cachexia to CRS. Identification of the exact mechanisms occurring in these conditions could potentially help in preventing and treating this deadly combination.

Relationship between periodontal disease and mortality in patients treated with maintenance hemodialysis

BACKGROUND

The relationship between periodontitis and outcomes in patients treated with long-term hemodialysis is controversial. Our previous work suggests that periodontitis is associated with malnutrition and inflammation. Here, we hypothesize that periodontitis is associated with mortality in hemodialysis patients.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

253 patients undergoing hemodialysis at a single hospital-based dialysis facility.

PREDICTOR

Severity of periodontal disease (mild, moderate, or severe based on oral examination of 6 teeth).

OUTCOMES & MEASUREMENTS

All-cause and cardiovascular mortality during a 6-year follow-up after an oral health examination of index teeth.

RESULTS

During the 6-year follow-up, 102 patients died. Death occurred in 70.6%, 41.8%, and 24.0% of patients with severe, moderate, and mild/no periodontitis, respectively. Using mild/no periodontitis as the reference group and adjustment for demographic characteristics, comorbid conditions, and selected laboratory values, HRs for all-cause mortality were 1.39 (95% CI, 0.83-2.34) and 1.83 (95% CI, 1.04-3.24) for moderate and severe periodontitis, respectively. HRs for cardiovascular mortality were not statistically significant.

LIMITATIONS

Single assessment of periodontal disease severity.

CONCLUSIONS

For patients undergoing long-term hemodialysis, periodontitis is associated with increased risk of death. Clinical trials are required to determine whether treatment of periodontitis decreases mortality.

High-calcium dialysate: a factor associated with inflammation, malnutrition and mortality in non-diabetic maintenance haemodialysis patients

AIM

Chronic inflammation, which is common in dialysis patients, often causes malnutrition and even protein-energy wasting. However, the association of high-calcium dialysate with malnutrition and/or inflammation in non-diabetic maintenance haemodialysis patients remains unclear. This study investigated the possible adverse effects of high-calcium dialysate and mortality in this population.

METHODS

A total of 717 non-diabetic haemodialysis patients participated in this 2 year prospective study. The subjects were categorized into three subgroups based on whether dialysate calcium concentrations were high (3.5 mEq/L), standard (3.0 mEq/L) or low (2.5 mEq/L). Demographic, haematological, nutritional and inflammatory markers, biochemical and dialysis-related data were obtained for cross-sectional analysis. Causes of death and mortality rates were also analyzed for each subgroup.

RESULTS

Patients with high-calcium dialysate (n = 82) had a higher incidence of malnutrition and inflammation (61.0% vs 44.1% and 43.9%, respectively) than those with standard- and low-calcium dialysate (n = 528 and 107). Backward stepwise multiple regression analysis revealed that high-calcium dialysate was negatively correlated with nutritional index, serum albumin levels, but positively associated with the inflammatory marker of serum ferritin levels. At the end of the 2 year follow up, 45 patients had died. Cox multivariate analysis demonstrated that high-calcium dialysate was a significant associated factor (relative risk 2.765; 95% confidence interval 1.429-5.352) for 2 year all-cause mortality in these patients.

CONCLUSION

The analytical results indicate that high-calcium dialysate is associated with malnutrition and inflammation as well as 2 year mortality in non-diabetic maintenance haemodialysis patients and the findings suggest that this population, even those with optimal mineral balance, should avoid high-calcium dialysate.

Diabetic nephropathy and risk factors for peripheral artery disease in Chinese with type 2 diabetes mellitus

The risk for peripheral arterial disease (PAD) is increased in patients with chronic kidney disease. We investigated the effects of renal function on PAD in Chinese with type 2 diabetes mellitus. This study enrolled a total of 2983 (1342 men and 1641 women) Chinese adults with diabetes. The mean age was 63.2 +/- 11.9 years. Peripheral arterial disease was diagnosed by an ankle-brachial index less than 0.9. Renal function was evaluated by serum creatinine (SCr), estimated glomerular filtration rate, and urinary albumin-creatinine ratio (ACR). Risk factors for PAD were evaluated using multiple logistic regression analysis. Age, cholesterol, and high-density lipoprotein cholesterol (HDL-C) (inverse association) were significant risk factors in men, whereas age, body mass index (inverse association), low-density lipoprotein cholesterol, and HDL-C (inverse association) were significant risk factors for diabetic women. After adjustment for age, body mass index, blood pressure, glycosylated hemoglobin, cholesterol, HDL-C, low-density lipoprotein cholesterol, and triglyceride levels, we found that SCr levels greater than 1.5 mg/dL, estimated glomerular filtration rate less than 60 mL/min, and urinary ACR greater than 30 mg/g were independent risk factors for PAD in diabetic men and that SCr levels greater than 1.4 mg/dL and urinary ACR greater than 30 mg/g were independently associated with PAD in diabetic women. The risk factors for PAD are somewhat different between men and women with diabetes in Chinese population in Taiwan. Diabetic nephropathy is significantly associated with PAD in this patient population.

Postprandial intradialytic dysglycaemia and diabetes in maintenance haemodialysis patients

BACKGROUND

Although the risk of developing dysglycaemia has been investigated in different communities this incidence is poorly studied in patients on maintenance haemodialysis (MHD).

MATERIALS AND METHODS

In a multicentre observational cohort study the occurrence of dysglycaemia was assessed in 239 primary normoglycaemic end stage renal disease (ERSD) patients on MHD. Dysglycaemia (fasting blood glucose > 110 mg dL(-1), > 140 mg dL(-1) 2 h after food intake) or diabetes (fasting blood glucose > 126 mg dL(-1) or > 200 mg dL(-1) at any time) were defined according to WHO criteria and cases were compared with age matched controls within the cohort.

RESULTS

Dysglycaemia was found in 82 primary normoglycaemic ESRD patients (34%) within 31 months after initiation of MHD. In 31 of these patients type 2 diabetes was diagnosed. When compared with matched control MHD patients differences in body mass index (BMI), HbA1c and postprandial blood glucose were detectable (P < 0.05). Increments in 0.1% of HbA1c were related with 11% higher odds for dysglycaemia (P = 0.002). In a subgroup of 36 primary normoglycaemic MHD patients who developed dysglycaemia event-free survival was 64%, 53%, 31%, 17% and 11% after 1, 2, 3, 4 and 5 years of haemodialysis treatment.

CONCLUSION

Onset of dysglycaemia or diabetes is frequent in ESRD patients after onset of chronic haemodialysis. Routine measurement of blood glucose before and after haemodialysis should be implemented as a standard of care during MHD.

Blood lead levels, malnutrition, inflammation, and mortality in patients with diabetes treated by long-term hemodialysis

BACKGROUND

Blood lead levels (BLLs) are associated with mortality in the general population. The clinical significance of BLLs in long-term hemodialysis (HD) patients with diabetes is unknown.

STUDY DESIGN

A cross-sectional and 1-year prospective study.

SETTINGS & PARTICIPANTS

211 patients with diabetes on long-term HD therapy at 3 centers.

PREDICTOR

BLLs measured before HD at baseline, categorized as abnormal (>20 microg/dL), high normal (10 to 20 microg/dL), and low normal (<10 microg/dL).

OUTCOMES & MEASUREMENTS

Malnutrition, defined as serum albumin level less than 3.6 g/dL, and inflammation, defined as high-sensitivity C-reactive protein level greater than 3 mg/dL, for cross-sectional analyses. Mortality and cause of death for longitudinal analyses.

RESULTS

34, 112, and 65 patients had abnormal, high-normal, and low-normal BLLs at baseline. At baseline, patients with abnormal BLLs had a greater proportion of malnutrition (14.7% versus 1.5% and 11.6%; P = 0.01) and inflammation (76.5% versus 52.3% and 50.9%; P = 0.01) than those with low- and high-normal BLLs. Backward stepwise regression analysis found that high-sensitivity C-reactive protein level correlated positively and albumin level correlated negatively with BLLs after other confounders were adjusted. At the end of follow-up, 16 patients had died. Kaplan-Meier analysis showed that patients with an abnormal BLL had greater mortality than those with low and low-normal BLLs (P = 0.004).

LIMITATIONS

Small sample size, sparse outcomes, and limited follow-up.

CONCLUSIONS

BLL may contribute to inflammation and nutritional status in long-term HD patients with diabetes on long-term HD therapy and may relate to 1-year mortality in these patients.

Ghrelin variants influence development of body mass index and plasma levels of total cholesterol in dialyzed patients

BACKGROUND

Ghrelin is an endogenous hormone expressed predominantly in the stomach. Ghrelin controls growth hormone secretion and also affects the body's energy balance. We analyzed the association of ghrelin variants with body mass index (BMI), albumin as a marker of malnutrition and plasma lipids as risk factors for atherosclerosis in hemodialyzed patients, in whom malnutrition and accelerated atherosclerosis are common complications.

METHODS

Ghrelin variants Arg51>Gln and Leu72> Met were analyzed by PCR-RFLP in 210 hemodialyzed patients, prospectively followed up for 15 months. Changes in body mass index, triglycerides, total cholesterol and albumin over time (after 3, 6, 9, 12 and 15 months of dialysis) were analyzed in subgroups divided according to ghrelin genotypes.

RESULTS

Carriers of at least one of the Gln51 and Met72 alleles lost body weight more quickly than Arg51Arg/Leu72Leu homozygotes (p<0.01). Carriers of the Gln51 allele were at higher risk of developing high cholesterol levels (p<0.01).

CONCLUSIONS

Common ghrelin variants may have an effect on changes in biochemical and anthropometric parameters in hemodialyzed patients over time and could be used in the future to plan individualized therapy.

Cytokine gene polymorphism and progression of renal and cardiovascular diseases

Cytokines are important modulators of inflammation. The balance between pro- and anti-inflammatory cytokines determines whether the intensity of inflammatory response is within physiological limits or in the pathological range. The cytokine network is highly complex, containing interactive cascades of gene activation and suppression. Both chronic kidney disease (CKD) and end-stage renal disease (ESRD) are characterized by elevated levels of proinflammatory cytokines and markers of inflammation. Cytokines may modulate the risk for progression of renal disease and the susceptibility to cardiovascular disease (CVD). Polymorphisms of cytokine genes may influence gene transcription and cytokine secretion and thereby modulate the risk of progression of renal and CVDs. The observed inconsistencies in the data regarding associations between single-nucleotide gene polymorphisms (SNPs) and their presumed phenotypic expression emphasize the need to recognize several conceptual and methodological aspects such as haplotypic rather than single SNP variations and the influence of pathway genes with synergistic or antagonistic effects that ultimately determine the phenotype. It is conceivable that when a patient with a high-risk cytokine genotype develops CKD, the risk for CVD is increased. Early interventions in CKD patients with high-risk genotypes may slow the progression of renal disease and also decrease CV mortality and morbidity.

Place of genotyping and phenotyping in understanding and potentially modifying outcomes in peritoneal dialysis patients

With the landmark publication of the human genome sequence and its subsequent division into haplotype blocks, the characterization of genetic variations is becoming a feasible approach to study both the pathophysiology and risk factors of complex traits. A number of strategies are available today for identifying candidate genes or polymorphisms associated with pertinent phenotypes. For Mendelian diseases with high penetrance owing to mutations in a single gene, such as polycystic kidney disease, linkage studies have been very successful in mapping the disease loci owing to the availability of families with multiple affected members. In contrast to monogenic conditions, complex diseases such as end-stage renal disease (ESRD) and complex traits such as individual variations in membrane transport and complications during the course of peritoneal dialysis (PD) therapy have a number of competing determinants and inhibitors, both genetic and environmental. Current results reflect this complexity, with few studies showing a large effect of any single risk factor on survival or outcome on PD. However, these studies have so far been small (less than 500 patients) and have not utilized bioinformatics or novel technologies (e.g., multiplex genotyping equipment). In the following review, we outline current approaches for using genetic data in clinical studies as well as highlight some of the most promising results in ESRD patients, particularly those on PD.

Sex Difference in the Distribution of Atherosclerotic Risk Factors and Their Association With Peripheral Arterial Disease in Taiwanese Type 2 Diabetic Patients

BACKGROUND

There appear to be sex differences in the risk factors for peripheral arterial disease (PAD) in type 2 diabetic patients, but studies in Taiwanese patients have not been conducted.

METHODS AND RESULTS

A total of 610 (268 men, 342 women) Taiwanese patients aged 63.3+/-10.8 years were evaluated. PAD was diagnosed by an ankle - brachial index <0.9. Risk factors included age, sex, body mass index (BMI), waist circumference (WC), smoking, menopause, diabetes duration, hypertension, insulin therapy, systolic and diastolic blood pressures, fasting glucose, total cholesterol (TC), triglyceride (TG), high- (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), apolipoproteins A1 (ApoA1) and B (ApoB) and uric acid (UA). When compared with the men, the women were significantly older and had longer duration, smaller WC, higher levels of systolic blood pressure, TC, TG, HDL-C, LDL-C, ApoA1 and ApoB, lower levels of UA, fewer smokers and more insulin users. Stepwise logistic regression showed age, BMI (inverse association) and systolic blood pressure as independent risk factors for men [respective odds ratios (OR): 1.080 (1.024-1.139), 0.832 (0.713-0.971) and 1.028 (1.005-1.051)]; and for women they were age, UA and insulin therapy [respective OR: 1.113 (1.056-1.173), 1.340 (1.101-1.630) and 4.173 (1.974-8.824).

CONCLUSIONS

PAD risk factors differ significantly between the sexes.

Does Periodontitis Reflect Inflammation and Malnutrition Status in Hemodialysis Patients?

BACKGROUND

Chronic infection and inflammation, including periodontitis, is linked to an increased risk for atherosclerosis. To investigate the possible adverse effects of periodontitis in maintenance hemodialysis patients, we compared periodontal severity with malnutrition and inflammation, which are associated with poor atherosclerotic outcome in hemodialysis patients.

METHODS

Two hundred fifty-three hemodialysis patients were included in this study to evaluate clinical periodontal status by using the Plaque Index, Gingival Index, and Periodontal Disease Index. Geographic, hematologic, biochemical, and dialysis-related data also were collected. Values for nutritional and inflammatory markers, such as albumin, blood urea nitrogen, creatinine, transferrin, absolute lymphocyte count, normalized protein catabolic rate, high-sensitivity C-reactive protein, and ferritin, were included for analysis with the Periodontal Index.

RESULTS

Poor oral health status was shown by 80.6% of hemodialysis patients with periodontal disease. In an analysis of geographic and disease-related parameters, we found that aging, smoking, diabetes, and longer dialysis duration were associated with severity of periodontitis. Parameters of malnutrition and inflammation also were associated with poor periodontal status. We next conducted multiple regression analysis and found that age, diabetes, smoking, albumin level, and dialysis duration were associated independently with periodontitis severity in hemodialysis patients. According to the severity of periodontitis, there were higher percentiles of patients with malnutrition (chi-square = 13.055; P = 0.005) and inflammation (chi-square = 10.046; P = 0.018) in the severe group.

CONCLUSION

Periodontal health is poor in hemodialysis patients and correlates with markers of malnutrition and inflammation. Its diagnosis and treatment deserve better awareness.

Prevalence and risk factors for stroke in Type 2 diabetic patients in Taiwan: a cross-sectional survey of a national sample by telephone interview

AIMS

To determine the prevalence and risk factors for stroke in patients with Type 2 diabetes mellitus (T2DM) and the age-specific prevalence odds ratios (POR) in comparison with the general population in Taiwan.

METHODS

A total of 16 994 T2DM patients were randomly selected for telephone interview from a group covered by the National Health Insurance programme. Lifetime prevalence of stroke was calculated and various risk factors were analysed. Age-specific POR was calculated using previously reported prevalence of stroke in the general population from a nationwide survey across Taiwan. Standardized prevalence and POR were also calculated using the 2000-2025 population of the World Health Organization.

RESULTS

A total of 12 531 cases (73.7%) were successfully interviewed. Stroke prevalence was 7.5%. In multivariate logistic regression, independent predictors were: increasing age, male gender, lower body mass index, ex-smokers, hyperlipidaemia, systolic pressure (or diastolic pressure when systolic pressure was not adjusted), education level below high school, and living in eastern or southern Taiwan. When compared with the general population, POR for stroke in the age groups < 45, 45-54, 55-64 and > or = 65 years were 82.29 (9.60, 705.57), 5.43 (2.33, 12.68), 3.73 (2.20, 6.33) and 2.14 (1.59, 2.89), respectively. The age-standardized prevalence of stroke was 2.3% in the diabetic patients and 0.6% in the general population.

CONCLUSIONS

Stroke prevalence in Taiwanese T2DM is 7.5%. Diabetic patients have a higher risk of stroke than the general population, but the relative risk attenuates with age. Besides conventional atherosclerotic risk factors, stroke patients in Taiwan are characterized by lower body mass index, lower education level and residence in southern or eastern Taiwan. The negative association between body mass index and stroke in Taiwanese T2DM is in contrast to the generally accepted concept that obesity is a major risk factor as seen in most western countries.

Methodological Considerations in the Study of Genetic Discrimination

The potential significance and dimensions of genetic discrimination have been described extensively in published literature, but epidemiological and verified case data are limited. Obtaining unbiased data from individuals about discrimination which has been based on erroneous or unjustifiable assumptions about their genetic predispositions poses unique challenges. Through review and discussion of research literature, we identify methodological considerations for collecting valid epidemiological data on genetic discrimination from individuals in the community; in particular, we consider issues which relate to sampling, selection and response. We identify issues to promote sound study design, with particular attention to verification of genetic discrimination, and highlight the importance of clinical and genetic knowledge of complex genotype-phenotype relationships.