Genome-wide association study of plasma resistin levels identified rs1423096 and rs10401670 as possible functional variants in the Japanese population

Resistin is a cytokine inducing insulin resistance in mice. We previously identified single nucleotide polymorphisms (SNPs) at -420 (rs1862513) and -358 (rs3219175) located in the human resistin gene (RETN) promoter as strong determinants for circulating resistin in the Japanese population. The objective was to identify additional functional variants for circulating resistin. We conducted a genome-wide association study in 448 Japanese subjects. A peak association signal was found on chromosome 19 where RETN is located. The top-hit SNP was SNP -358 G>A, followed by rs1423096 C>T, SNP -420 C>G, and rs10401670 C>T (P = 5.39×10^-47, 1.81×10^-22, 2.09×10^-16, and 9.25×10^-15, respectively). Meta-analysis including another two independent general Japanese populations showed that circulating resistin was most strongly associated with SNP-358, followed by SNP-420, rs1423096, and rs10401670. Rs1423096 and rs10401670 were located in the 3'-region of RETN and were in strong linkage disequilibrium. Although these SNPs were also in linkage disequilibrium with the promoter SNPs, conditional and haplotype association analyses identified rs1423096 and rs10401670 as independent determinants for circulating resistin. Functionally, nuclear proteins specifically recognized T but not C at rs10401670 as evidenced by an electrophoretic mobility shift assay. The promoter activity of a luciferase reporter with T at either rs1423096 or rs10401670 was lower than that with C in THP-1 human monocytes. Therefore, rs1423096 and rs10401670, in addition to SNP-420 and SNP-358, were identified as possible functional variants affecting circulating resistin by the genome-wide search in the Japanese population.

Abstract P262: Spot Urine Sodium to Potassium Ratio Predicts Increasing Blood Pressure Levels in a General Population: The Nagahama Study

Excessive salt intake is a risk factor for hypertension. The most reliable method for estimating daily salt intake is measurement of 24-h urinary sodium excretion, while it is inconvenient. Sodium-to-potassium ratio (Na/K) of a urine sample is another index of salt loading. We previously reported that a simple measure of spot urine Na/K might be a representative of salt loading in a cross-sectional setting. Here, we conducted a longitudinal study aiming to clarify a prognostic significance of spot urine Na/K for increasing blood pressure (BP) levels. Study subjects consists of 9,769 general individuals. Among them, individuals whose baseline Na/K was available (n=9,328), who were normotensive at baseline (n=6,392), and who participated in the follow-up measurement (n=5,209) were included in this analysis (51.8±12.9 years old, male: 29.2%). Mean follow-up duration was 5.0±0.5 years. Mean Na/K at baseline was 3.1±1.7, and showed step-wise increase with BP levels (optimal: 3.0±1.6, normal: 3.3±1.8, high normal: 3.4±1.8, P<0.001). Other major factors that were significantly associated with Na/K was fasting time (r=-0.220, P<0.001), and CKD (CKD (n=694): 2.7±1.6, control: 3.2±1.7, P<0.001). Mean SBP was significantly increased during follow-up period (baseline: 116±12, follow-up: 119±15 mmHg), and 805 individuals (15.5%) were newly diagnosed as hypertension (HT). These individuals were significantly older (HT: 60.3±9.9, NT: 50.3±12.8 years), were frequently male (36.4%, 27.9%), and had higher SBP (127±9, 115±11 mmHg) at baseline (P<0.001). In contrast, baseline spot urine Na/K was slightly lower in individuals who developed HT (3.0±1.6, 3.1±1.8, P=0.013), while that measured at follow-up investigation was oppositely higher in hypertensives (3.1±1.8, 2.8±1.5, P<0.001). Multiple linear regression analysis adjusted for the covariates identified baseline Na/K (β=0.108, P<0.001) and changes in Na/K during follow-up period (β=0.222, P<0.001) as independent determinants for future SBP levels. Higher spot urine Na/K, as well as increases in the Na/K levels, was significant determinant for future BP levels. The apparently lower baseline Na/K levels in individuals who developed HT might be due to reverse causality.

Mendelian randomization analysis in three Japanese populations supports a causal role of alcohol consumption in lowering low-density lipid cholesterol levels and particle numbers

BACKGROUND AND AIMS

While alcohol consumption is known to increase plasma high-density lipoprotein (HDL) cholesterol levels, its relationship with low-density lipoprotein (LDL) cholesterol levels is unclear. Aldehyde dehydrogenase 2 (ALDH2) is a rate-controlling enzyme in alcohol metabolism, but a large number of Japanese people have the inactive allele. Here, we conducted a Mendelian randomization analysis using the ALDH2 genotype to clarify a causal role of alcohol on circulating cholesterol levels and lipoprotein particle numbers.

METHODS

This study was conducted in three independent general Japanese populations (men, n = 2289; women, n = 1940; mean age 63.3 ± 11.2 years). Alcohol consumption was assessed using a questionnaire. Lipoprotein particle numbers were determined by nuclear magnetic resonance spectroscopy.

RESULTS

Alcohol consumption increased linearly in proportion to the number of subjects carrying the enzymatically active *1 allele in men (p < 0.001). The *1 allele was also positively associated with HDL cholesterol level (adjusted mean ± standard error, *1*1: 60 ± 0.5, *1*2: 56 ± 0.6, *2*2: 55 ± 1.3 mg/dl, p < 0.001) and inversely associated with LDL cholesterol level (116 ± 0.9, 124 ± 1.1, 130 ± 2.6 mg/dl, p < 0.001). The *1 allele was also positively associated with HDL particle numbers (per-allele: 2.60 ± 0.32 μmol/l, p < 0.001) and inversely associated with LDL particle numbers (-67.8 ± 19.6 nmol/l, p = 0.001). Additional Mendelian randomization analysis failed to clarify the involvement of cholesteryl ester transfer protein in alcohol-related changes in lipoprotein cholesterol levels. No significant association was observed in women, presumably due to their small amount of alcohol intake.

CONCLUSIONS

Alcohol consumption has a causal role in not only increasing HDL cholesterol levels but also decreasing LDL cholesterol levels and particle numbers.

Mouth breathing, another risk factor for asthma: the Nagahama Study

BACKGROUND

Allergic rhinitis, a known risk factor for asthma onset, often accompanies mouth breathing. Mouth breathing may bypass the protective function of the nose and is anecdotally considered to increase asthma morbidity. However, there is no epidemiological evidence that mouth breathing is independently associated with asthma morbidity and sensitization to allergens. In this study, we aimed to clarify the association between mouth breathing and asthma morbidity and allergic/eosinophilic inflammation, while considering the effect of allergic rhinitis.

METHODS

This community-based cohort study, the Nagahama Study, contained a self-reporting questionnaire on mouth breathing and medical history, blood tests, and pulmonary function testing. We enrolled 9804 general citizens of Nagahama City in the Shiga Prefecture, Japan.

RESULTS

Mouth breathing was reported by 17% of the population and was independently associated with asthma morbidity. The odds ratio for asthma morbidity was 1.85 (95% CI, 1.27-2.62) and 2.20 (95% CI, 1.72-2.80) in subjects with mouth breathing alone and allergic rhinitis alone, which additively increased to 4.09 (95% CI, 3.01-5.52) when mouth breathing and allergic rhinitis coexisted. Mouth breathing in nonasthmatics was a risk for house dust mite sensitization, higher blood eosinophil counts, and lower pulmonary function after adjusting for allergic rhinitis.

CONCLUSION

Mouth breathing may increase asthma morbidity, potentially through increased sensitization to inhaled allergens, which highlights the risk of mouth-bypass breathing in the 'one airway, one disease' concept. The risk of mouth breathing should be well recognized in subjects with allergic rhinitis and in the general population.

Genome-Wide Association Study of Absolute QRS Voltage Identifies Common Variants of TBX3 as Genetic Determinants of Left Ventricular Mass in a Healthy Japanese Population

Left ventricular hypertrophy (LVH) represents a common final pathway leading to heart failure. We have searched for genetic determinants of left ventricular (LV) mass using values for absolute electrocardiographic QRS voltage in a healthy Japanese population. After adjusting for covariates, the corrected S and R wave voltages in leads V1 and V5 from 2,994 healthy volunteers in the Japan Pharmacogenomics Data Science Consortium (JPDSC) database were subjected to a genome-wide association study. Potential associations were validated by an in silico replication study using an independent Japanese population obtained from the Nagahama Prospective Genome Cohort for Comprehensive Human Bioscience. We identified a novel association between the lead V5, R wave voltage in Japanese individuals and SNP rs7301743[G], which maps near the gene encoding T-box transcription factor Tbx3. Meta-analysis of two independent Japanese datasets demonstrated a marginally significant association of SNP rs7301743 in TBX3|MED13L with a 0.071 mV (95% CI, 0.038–0.11 mV) shorter R wave amplitude in the V5 lead per minor allele copy (P = 7.635 x 10⁻⁸). The transcriptional repressor, TBX3, is proposed to suppress the development of working ventricular myocardium. Our findings suggest that genetic variation of Tbx3 is associated with LV mass in a healthy Japanese population.

Association of office-based frailty score with hypertensive end organ damage in the J-SHIPP cross-sectional study

BACKGROUND

Frailty, a geriatric syndrome reflecting a state of reduced physiological reserve and increased vulnerability, is an independent risk factor for cardiovascular morbidity and mortality. However, the relationship between frailty and hypertensive end-organ damage is not fully established.

METHOD AND RESULTS

We performed a cross-sectional study to investigate the association between frailty and end-organ damage in 1125 apparently healthy middle-aged to elderly subjects. We performed a simple frailty (SF) score that was easily obtainable in the office, in combination with low hand grip power and short one-leg standing (OLS) time. The association between SF score and hypertensive end-organ damage and other frailty-related parameters was evaluated. Odds ratio of SF score 1 to score 0 for the presence of hypertension was 1.9 [1.4-2.5, p<.0001] and that of SF score 2 was 3.3 [2.1-5.3, p<.0001]. SF score was also significantly associated with brachial-ankle pulse wave velocity (baPWV) and central pulse pressure (PP2). SF score was significantly associated with higher frailty index calculated from 21 parameters, lower cognitive test score, % vital capacity, skeletal muscle mass, and thigh muscle cross-sectional area. SF score was positively associated with stage of brain white matter hyperintenisty, plasma levels of B-type natriuretic peptide, and urinary protein excretion, even after correction for confounding parameters including baPWV and PP2.

CONCLUSIONS

These findings indicate that frailty is significantly associated with end-organ damage in elderly subjects. SF score may be a useful clinical tool to identify frail subjects and advanced end-organ damage in elderly subjects.

Relationship Among Chlamydia and Mycoplasma Pneumoniae Seropositivity, IKZF1 Genotype and Chronic Obstructive Pulmonary Disease in A General Japanese Population: The Nagahama Study

Chronic obstructive pulmonary disease (COPD) is a possible risk factor for cardiovascular disease. The association of COPD with the pathogenicity of infection with Chlamydia pneumoniae and Mycoplasma pneumoniae is controversial. We conducted a cross-sectional study to clarify the association between atypical pneumoniae seropositivity and COPD in a general population. We also investigated genetic polymorphisms conferring susceptibility to a pneumonia titer. The study included 9040 Japanese subjects (54 ± 13 years). COPD was defined as a ratio of forced expiratory volume in 1 second to forced vital capacity of less than 70%. Serum levels of IgA and IgG antibodies to C pneumoniae were determined using an enzyme-linked immunoassay, and M pneumoniae seropositivity was assessed by a particle agglutination test. Subjects seropositive for C pneumoniae (26.1%) had a higher prevalence of COPD (seropositive, 5.8%; seronegative, 3.1%; P < 0.001) after adjustment for age, sex, height, weight, and smoking status. The association between M pneumoniae seropositivity (20.4%) and COPD was also significant in covariate-adjusted analysis (P < 0.001). A genome-wide association analysis of the C pneumoniae IgA index identified a susceptible genotype (rs17634369) near the IKZF1 gene, and the seropositive rate of C pneumoniae significantly differed among genotypes (AA, 22.5; AG, 25.3; GG, 29.7%, P < 0.001). On multiple regression analysis, seropositivity for both C pneumoniae (odds ratio = 1.41, P = 0.004) and M pneumoniae (odds ratio = 1.60, P = 0.002) was an independent determinant for COPD, while no direct association was found with the rs17634369 genotype. Seropositivity for both C pneumoniae and M pneumoniae is an independent risk factor for COPD in the general population.

Rheumatoid Factor Is Associated With the Distribution of Hand Joint Destruction in Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic disease leading to joint destruction. Although many studies have addressed factors potentially correlated with the speed of joint destruction, less attention has been paid to the distribution of joint destruction in patients with RA. In this study, destruction of the hand bones in patients with RA was classified into 2 anatomic subgroups, the fingers and the non-fingers, with the aim of analyzing which factors are associated with destruction of the finger joints.

METHODS

A total of 1,215 Japanese patients with RA were recruited from 2 different populations. The degree of joint destruction was assessed using the total modified Sharp/van der Heijde score (SHS) of radiographic joint damage. The SHS score of joint damage in the finger joints was used as the dependent variable, and the SHS score in the non-finger joints was used as a covariate. Age, sex, disease duration, smoking, C-reactive protein level, treatment for RA, and positivity for and levels of anti-citrullinated protein antibodies and rheumatoid factor (RF) were evaluated as candidate correlates. Overall effect sizes were assessed in a meta-analysis. In addition, associations observed in the Japanese patients were compared to those in a cohort of 157 Dutch RA patients in the BeSt study (a randomized, controlled trial involving 4 different strictly specified treatment strategies for early RA).

RESULTS

Not surprisingly, disease duration in Japanese patients with RA was associated with the finger SHS score (P ≤ 0.00037). Both positivity for and levels of RF showed significant associations with the finger SHS score after adjustment for covariates (P = 0.0022 and P = 8.1 × 10(-7) , respectively). These associations were also true in relation to the time-averaged finger SHS score. An association between RF positivity and the finger SHS score was also observed in Dutch patients with RA in the BeSt study (P = 0.049).

CONCLUSION

Positivity for and levels of RF are associated with finger joint destruction independent of non-finger joint destruction and other covariates. Our findings suggest that there are different mechanisms of joint destruction operating in the finger joints of patients with RA.

Usefulness of the second derivative of the finger photoplethysmogram for assessment of end-organ damage: the J-SHIPP study

Early detection of pathological changes in the vasculature is required to identify individuals at risk of cardiovascular diseases. Noninvasive measurement of the second derivative of photoplethysmogram (SDPTG) might aid in evaluating vascular aging. Here we clarified the diagnostic significance of four SDPTG indices for end-organ damage. A total of 1613 community residents (65±10 years) were enrolled. Changes in blood flow volume at the forefinger were measured by photoplethysmography. SDPTG was computationally calculated from the plethysmogram, and the height of five peaks (a-e) on the SDPTG was measured. Carotid intima-media thickness (IMT), brachial-to-ankle pulse wave velocity (baPWV) and silent cerebral lesions were used as indices of end-organ damage. Multivariate analysis identified age, sex, systolic blood pressure and heart rate as strong determinants for the evaluated SDPTG indices, namely b/a, d/a and aging index ([b-d-c-e]/a). In addition, poor glycemic control and carotid IMT were also weakly associated with the SDPTG indices. Compared with other established risk factors, however, the association between the SDPTG indices and carotid IMT was weak or insignificant (b/a: β=0.069, P=0.002; d/a: β=-0.009, P=0.669; and aging index: β=0.047, P=0.037). Further, no significant association was noted between the SDPTG indices and silent lacunar infarction (b/a: P=0.111; d/a: P=0.263; and aging index: P=0.167) and periventricular hyperintensity (b/a: P=0.587; d/a: P=0.254; and aging index: P=0.429). Although the SDPTG indices evaluated here might represent structural and functional changes in arteries, they exhibited limited diagnostic significance for pathophysiological changes in large arteries, as well as small vessel diseases of the brain.

Genome-wide association studies in East Asians identify new loci for waist-hip ratio and waist circumference

Sixty genetic loci associated with abdominal obesity, measured by waist circumference (WC) and waist-hip ratio (WHR), have been previously identified, primarily from studies conducted in European-ancestry populations. We conducted a meta-analysis of associations of abdominal obesity with approximately 2.5 million single nucleotide polymorphisms (SNPs) among 53,052 (for WC) and 48,312 (for WHR) individuals of Asian descent, and replicated 33 selected SNPs among 3,762 to 17,110 additional individuals. We identified four novel loci near the EFEMP1, ADAMTSL3 , CNPY2, and GNAS genes that were associated with WC after adjustment for body mass index (BMI); two loci near the NID2 and HLA-DRB5 genes associated with WHR after adjustment for BMI, and three loci near the CEP120, TSC22D2, and SLC22A2 genes associated with WC without adjustment for BMI. Functional enrichment analyses revealed enrichment of corticotropin-releasing hormone signaling, GNRH signaling, and/or CDK5 signaling pathways for those newly-identified loci. Our study provides additional insight on genetic contribution to abdominal obesity.

Synergistic association of elevated serum free fatty acid and glucose levels with large arterial stiffness in a general population: The Nagahama Study

BACKGROUND

Previous studies have reported that artificial increases in circulating free fatty acid (FFA) levels might have adverse effects on the vasculature. However, whether or not this effect can be extrapolated to physiological variations in FFA levels has not been clarified. Given that FFAs exert a lipotoxic effect on pancreatic β-cells and might directly damage the arterial endothelium, we hypothesized that these adverse effects might synergize with hyperglycemia.

METHODS

A total of 9396 Japanese subjects were included in the study. Serum FFA levels were measured at baseline examination. Brachial-to-ankle pulse wave velocity (baPWV) was measured as an index of arterial stiffness.

RESULTS

As serum levels of FFA were markedly lower in subjects with higher insulin level, a significant association between FFA levels and baPWV was observed only in subjects with blood samples taken under fasting (≥12 h, P<0.001) or near-fasting (5-11 h, P<0.001) conditions, and not in those taken under non-fasting (<5 h, P=0.307) conditions. Although type 2 diabetes and HbA1c showed a strong association with baPWV, the association between FFA level and baPWV remained significant (β=0.052, P<0.001) after adjustment for glycemic levels. In addition to their direct relationship, FFA and glucose levels were synergistically associated with baPWV (FFA(⁎)glucose; β=0.036, P<0.001). Differences in baPWV between the lowest and highest subgroups divided by a combination of FFA and glucose reached approximately 300 cm/s.

CONCLUSIONS

Physiological variations in FFA concentrations might be a risk factor for large arterial stiffness. FFA and hyperglycemia exert a synergistic adverse effect on the vasculature.

Mapping the genetic diversity of HLA haplotypes in the Japanese populations

Japan has often been viewed as an Asian country that possesses a genetically homogenous community. The basis for partitioning the country into prefectures has largely been geographical, although cultural and linguistic differences still exist between some of the districts/prefectures, especially between Okinawa and the mainland prefectures. The Major Histocompatibility Complex (MHC) region has consistently emerged as the most polymorphic region in the human genome, harbouring numerous biologically important variants; nevertheless the presence of population-specific long haplotypes hinders the imputation of SNPs and classical HLA alleles. Here, we examined the extent of genetic variation at the MHC between eight Japanese populations sampled from Okinawa, and six other prefectures located in or close to the mainland of Japan, specifically focusing at the haplotypes observed within each population, and what the impact of any variation has on imputation. Our results indicated that Okinawa was genetically farther to the mainland Japanese than were Gujarati Indians from Tamil Indians, while the mainland Japanese from six prefectures were more homogeneous than between northern and southern Han Chinese. The distribution of haplotypes across Japan was similar, although imputation was most accurate for Okinawa and several mainland prefectures when population-specific panels were used as reference.

Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10(-11) to 5.0 × 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.

Knee Pain and Low Back Pain Additively Disturb Sleep in the General Population: A Cross-Sectional Analysis of the Nagahama Study

Introduction

Association of knee and low back pain with sleep disturbance is poorly understood. We aimed to clarify the independent and combined effects of these orthopedic symptoms on sleep in a large-scale general population.

Methods

Cross-sectional data about sleep and knee/low back pain were collected for 9,611 community residents (53±14 years old) by a structured questionnaire. Sleep duration less than 6 h/d was defined as short sleep. Sleep quality and the presence of knee and low back pain were evaluated by dichotomous questions. Subjects who complained about knee or low back pains were graded by tertiles of a numerical response scale (NRS) score and a Roland-Morris disability questionnaire (RDQ) score respectively. Multivariate regression analyses were performed to determine the correlates of short sleep duration and poor sleep quality.

Results

Frequency of participants who complained of the orthopedic symptoms was as follows; knee pain, 29.0%; low back pain, 42.0% and both knee and low back pain 17.6%. Both knee and low back pain were significantly and independently associated with short sleep duration (knee pain: odds ratio (OR) = 1.19, p<0.01; low back pain: OR = 1.13, p = 0.01) and poor sleep quality (knee pain: OR = 1.22, p<0.01; low back pain; OR = 1.57, p<0.01). The group in the highest tertile of the NRS or RDQ score had the highest risk for short sleep duration and poor sleep quality except for the relationship between the highest tertile of the RDQ score and short sleep duration.(the highest tertile of the NRS: OR for short sleep duration = 1.31, p<0.01; OR for poor sleep quality = 1.47, p<0.01; the highest tertile of the RDQ: OR for short sleep duration = 1.11, p = 0.12; OR for poor sleep quality = 1.81, p<0.01) Further, coincident knee and low back pain raised the odds ratios for short sleep duration (either of knee or low back pain: OR = 1.10, p = 0.06; both knee and low back pain: OR = 1.40, p<0.01) and poor sleep quality (either of knee or low back pain: OR = 1.61, p<0.01; both knee and low back pain: OR = 2.17, p<0.01).

Conclusion

Knee and low back pains were independently associated with short sleep duration and poor sleep quality. Further, they additively increased the correlation with these sleep problems in the general population.

Abstract P164: White-coat Hypertension is a Factor Relating Postural Blood Pressure Dysregulation and Cardiovascular Risks

Backgrounds: Postural blood pressure (BP) dysregulation particularly orthostatic hypotension is a phenomenon that is frequently observed in elderly persons and has been reported to be a prognostic factor for incidence of cardiovascular diseases and mortality. White-coat and masked hypertension are another indices of blood pressure dysregulation and were also known to be a risk factor for cardiovascular outcomes. However, relationship between these common phenomena is yet unclear. Here we conducted a cross-sectional study to clarify the relationships.

Methods: Study subjects were 818 general persons. Homed BP was calculated from ambulatory monitored BPs as a mean of BPs measured during 1 hour after wake up. Orthostatic BP change was measured at 1 and 3 minutes after standing up and a maximum BP difference was used in the analysis.

Results: Home-to-clinic SBP differences were linearly and inversely associated with orthostatic SBP change (r=-0.321, p<0.001). Therefore, white-coat hypertensive subjects (10.3%, -9.3±13.3 mmHg) showed larger orthostatic BP decline than normotensive subjects (30.9%, -3.0±11.1 mmHg) and masked hypertensive subjects (24.7%, -0.4±12.1 mmHg, p<0.001). Home-to-clinic SBP differences (β=-0.150, p<0.001), but not orthostatic SBP change (β=-0.046, p=0.169), was significantly associated with carotid hypertrophy independently of basic covariates including clinic SBP.

Conclusion: Home-to-clinic SBP differences may be partially involved in the prognostic significance of orthostatic hypotension.

Association Between Genetic Variation in the SCN10A Gene and Cardiac Conduction Abnormalities in Patients With Hypertrophic Cardiomyopathy

Arrhythmias are associated with reduced quality of life and poor prognosis in patients with hypertrophic cardiomyopathy (HCM). Recent genome-wide association studies revealed that a nonsynonymous single nucleotide polymorphism, rs6795970, in the SCN10A gene was associated with the PR interval. We examined whether the PR prolonging allele (A allele) in the SCN10A gene may be associated with cardiac conduction abnormalities in HCM patients.We genotyped the polymorphism in 149 HCM patients. Conduction abnormalities were defined as first-degree heart block, bundle-branch block, and bifascicular heart block. Patients were divided into two groups: group A consisted of 122 patients (82%) without a conduction abnormality; and group B consisted of 27 patients (18%) with one or more cardiac conduction abnormalities. The frequency distribution of the SCN10A genotypes (G/G, G/A, and A/A) among the patients with HCM was 71%, 26%, and 3%, respectively. A cardiac conduction abnormality was documented in 9% with G/G and 40% with G/A or A/A. There was a significant difference in the genotype distribution between the two groups (P = 0.0002). In the dominant A allele model, there was a significant difference in genotypes between the two groups (P < 0.0001). In addition, the A allele remained significant after adjusting for other covariates in a multivariate model (odds ratio = 6.30 [95% confidence interval: 2.24 to 19.09], P = 0.0005).The rs6795970 in the SCN10A gene, which is reported to carry a high risk of heart block, might be associated with cardiac conduction abnormalities in HCM patients.

Association of postural instability with asymptomatic cerebrovascular damage and cognitive decline: the Japan Shimanami health promoting program study

BACKGROUND AND PURPOSE

Asymptomatic cerebral small-vessel disease (cSVD) in elderly individuals are potent risk factors for stroke. In addition to common clinical risk factors, postural instability has been postulated to be associated with cSVD in older frail patients. Here, we conducted a cross-sectional study to understand the possible link between postural instability and asymptomatic cSVD further, namely periventricular hyperintensity, lacunar infarction, and microbleeds, as well as cognitive function, in a middle-aged to elderly general population (n=1387).

METHODS

Postural instability was assessed based on one-leg standing time (OLST) and posturography findings. cSVD was evaluated by brain MRI. Mild cognitive impairment was assessed using a computer-based questionnaire, and carotid intima-media thickness as an index of atherosclerosis was measured via ultrasonography.

RESULTS

Frequency of short OLST, in particular <20 s, increased linearly with severity of cSVD (lacunar infarction lesion: none, 9.7%; 1, 16.0%; >2, 34.5%; microbleeds lesion: none, 10.1%; 1, 15.3%; >2, 30.0%; periventricular hyperintensity grade: 0, 5.7%; 1, 11.5%; >2, 23.7%). The association of short OLST with lacunar infarction and microbleeds but not periventricular hyperintensity remained significant even after adjustment for possible covariates (lacunar infarction, P=0.009; microbleeds, P=0.003; periventricular hyperintensity, P=0.601). In contrast, no significant association was found between posturographic parameters and cSVD, whereas these parameters were linearly associated with OLST. Short OLST was also significantly associated with reduced cognitive function independent of covariates, including cSVD (P=0.002).

CONCLUSIONS

Postural instability was found to be associated with early pathological changes in the brain and functional decline, even in apparently healthy subjects.

Significant association of periodontal disease with anti-citrullinated peptide antibody in a Japanese healthy population - The Nagahama study

Anti-citrullinated peptide antibody (ACPA) is a highly specific autoantibody to rheumatoid arthritis (RA). Recent studies have revealed that periodontal disease (PD) is closely associated with RA and production of ACPA in RA. Analyses of associations between PD and ACPA production in a healthy population may deepen our understandings. Here, we analyzed a total of 9554 adult healthy subjects. ACPA and IgM-rheumatoid factor (RF) was quantified and PD status was evaluated using the number of missing teeth (MT), the Community Periodontal Index (CPI) and Loss of Attachment (LA) for these subjects. PD status was analyzed for its association with the positivity and categorical levels of ACPA and RF conditioned for covariates which were shown to be associated with PD, ACPA or RF. As a result, all of MT, CPI and LA showed suggestive or significant associations with positivity (p = 0.024, 0.0042 and 0.037, respectively) and levels of ACPA (p ≤ 0.00031), but none of the PD parameters were associated with those of RF. These association patterns were also observed when we analyzed 6206 non-smokers of the participants. The significant associations between PD parameters and positivity and levels of ACPA in healthy population support the fundamental involvement of PD with ACPA production.

Effects of smoking and shared epitope on the production of anti-citrullinated peptide antibody in a Japanese adult population

OBJECTIVE

Anti-citrullinated peptide antibody (ACPA) and rheumatoid factor (RF) are markers to rheumatoid arthritis (RA). Smoking and shared epitope (SE) in HLA-DRB1 are associated with the production of these autoantibodies in RA. Detailed distribution and characterization of ACPA and RF in the general population have remained unclear. We aimed to evaluate positivity of ACPA and RF in a general Japanese population and to detect correlates, including genetic components.

METHODS

ACPA and RF were quantified in 9,804 Japanese volunteers ages 30-75 years. Logistic regression analyses were performed to evaluate the effects of candidates of correlates on the autoantibody positivity. A genome-wide association study (GWAS) was performed using 394,239 single nucleotide polymorphisms for 3,170 participants, and HLA-DRB1 alleles were imputed based on the GWAS data.

RESULTS

A total of 1.7% and 6.4% of subjects were positive for ACPA and RF, respectively, and the 2 markers showed a significant correlation (P = 2.0 × 10(-23) ). Old age was associated with ACPA positivity (P = 0.00062). Sex, smoking, SE, and other candidates of correlates did not have significant effects. Interaction between smoking and SE positivity was not apparent, but smoking showed a significant association with high levels of ACPA (P = 0.0019).

CONCLUSION

ACPA and RF could be detected in 1.7% and 6.4% of the Japanese adult population without RA, respectively. ACPA and RF were suggested to share mechanisms even in healthy populations. Old age was associated with increasing ACPA positivity. While positivity of ACPA and RF was not associated with SE and smoking, an association between high ACPA and smoking was observed.