Using genetics to test the causal relationship of total adiposity and periodontitis: Mendelian randomization analyses in the Gene-Lifestyle Interactions and Dental Endpoints (GLIDE) Consortium

Background: The observational relationship between obesity and periodontitis is widely known, yet causal evidence is lacking. Our objective was to investigate causal associations between periodontitis and body mass index (BMI).Methods: We performed Mendelian randomization analyses with BMI-associated loci combined in a genetic risk score (GRS) as the instrument for BMI. All analyses were conducted within the Gene-Lifestyle Interactions and Dental Endpoints (GLIDE) Consortium in 13 studies from Europe and the USA, including 49 066 participants with clinically assessed (seven studies, 42.1% of participants) and self-reported (six studies, 57.9% of participants) periodontitis and genotype data (17 672/31 394 with/without periodontitis); 68 761 participants with BMI and genotype data; and 57 871 participants (18 881/38 990 with/without periodontitis) with data on BMI and periodontitis.Results: In the observational meta-analysis of all participants, the pooled crude observational odds ratio (OR) for periodontitis was 1.13 [95% confidence interval (CI): 1.03, 1.24] per standard deviation increase of BMI. Controlling for potential confounders attenuated this estimate (OR = 1.08; 95% CI:1.03, 1.12). For clinically assessed periodontitis, corresponding ORs were 1.25 (95% CI: 1.10, 1.42) and 1.13 (95% CI: 1.10, 1.17), respectively. In the genetic association meta-analysis, the OR for periodontitis was 1.01 (95% CI: 0.99, 1.03) per GRS unit (per one effect allele) in all participants and 1.00 (95% CI: 0.97, 1.03) in participants with clinically assessed periodontitis. The instrumental variable meta-analysis of all participants yielded an OR of 1.05 (95% CI: 0.80, 1.38) per BMI standard deviation, and 0.90 (95% CI: 0.56, 1.46) in participants with clinical data.Conclusions: Our study does not support total adiposity as a causal risk factor for periodontitis, as the point estimate is very close to the null in the causal inference analysis, with wide confidence intervals

GWAS analysis of handgrip and lower body strength in older adults in the CHARGE consortium

Decline in muscle strength with aging is an important predictor of health trajectory in the elderly. Several factors, including genetics, are proposed contributors to variability in muscle strength. To identify genetic contributors to muscle strength, a meta-analysis of genomewide association studies of handgrip was conducted. Grip strength was measured using a handheld dynamometer in 27 581 individuals of European descent over 65 years of age from 14 cohort studies. Genomewide association analysis was conducted on ~2.7 million imputed and genotyped variants (SNPs). Replication of the most significant findings was conducted using data from 6393 individuals from three cohorts. GWAS of lower body strength was also characterized in a subset of cohorts. Two genomewide significant (P-value< 5 × 10−8) and 39 suggestive (P-value< 5 × 10−5) associations were observed from meta-analysis of the discovery cohorts. After meta-analysis with replication cohorts, genomewide significant association was observed for rs752045 on chromosome 8 (β = 0.47, SE = 0.08, P-value = 5.20 × 10−10). This SNP is mapped to an intergenic region and is located within an accessible chromatin region (DNase hypersensitivity site) in skeletal muscle myotubes differentiated from the human skeletal muscle myoblasts cell line. This locus alters a binding motif of the CCAAT/enhancer-binding protein-β (CEBPB) that is implicated in muscle repair mechanisms. GWAS of lower body strength did not yield significant results. A common genetic variant in a chromosomal region that regulates myotube differentiation and muscle repair may contribute to variability in grip strength in the elderly. Further studies are needed to uncover the mechanisms that link this genetic variant with muscle strength

Design und Qualitätskontrolle der zahnmedizinischen Untersuchung in der NAKO Gesundheitsstudie

BACKGROUND: Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated. OBJECTIVES: The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality. MATERIALS AND METHODS: A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level‑1 examination, the number of teeth and prostheses were recorded. As part of the level‑2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed. RESULTS: Analyses included data of 57,967 interview participants, 56,913 level‑1 participants and 6295 level‑2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners. CONCLUSIONS: The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC’s overall assessment program. However, rigorous dental support of the study centres is required for quality management.HINTERGRUND:Karies und Parodontitis sind weltweit hoch prävalente Erkrankungen. Durch ihre Erfassung im Rahmen der NAKO Gesundheitsstudie können Assoziationen zwischen oralen und systemischen Erkrankungen untersucht werden. FRAGESTELLUNG: In einer ersten Qualitätsanalyse zur Halbzeit der NAKO-Basiserhebung wird die Plausibilität der zahnmedizinischen Ergebnisse überprüft. Es werden Maßnahmen zur Verbesserung der Datenqualität vorgeschlagen. MATERIAL UND METHODEN: Ein zahnmedizinisches Interview, eine Speichelprobengewinnung und eine Befunderhebung wurden durchgeführt. Im Rahmen der Level-1-Untersuchung wurden Zahn- und Prothesenanzahl erfasst. In der Level-2-Untersuchung wurden detaillierte parodontologische, kariologische und funktionelle Befunde erhoben. Alle Untersuchungen wurden von geschultem nichtzahnmedizinischen Personal durchgeführt. Es wurden Plausibilitätsprüfungen durchgeführt sowie Verteilungen deskriptiv dargestellt. ERGEBNISSE: In die Analysen gingen Daten von 57.967 Interviewteilnehmer*innen, 56.913 Level-1- und 6295 Level-2-Teilnehmer*innen ein. Der Anteil fehlender Werte lag für die einzelnen Parameter der Level-1- und Level-2-Untersuchungen zwischen 0,02 % und 3,9 %. Die Parameter zeigten eine plausible Verteilung; vereinzelt wurden unplausible Werte beobachtet, z. B. beim horizontalen und vertikalen Überbiss (Overjet und Overbite). Anhand der Intraklassenkorrelationskoeffizienten wurden für die einzelnen Parameter Unterschiede zwischen regionalen Clustern, den Studienzentren und verschiedenen Untersucher*innen nachgewiesen. DISKUSSION: Die bisherigen Ergebnisse bestätigten die Umsetzbarkeit des Studienprotokolls durch nichtzahnmedizinisches Personal und die erfolgreiche Integration in das Untersuchungsprogramm der NAKO Gesundheitsstudie. Die Studienzentren benötigen eine intensive zahnmedizinische Betreuung für das Qualitätsmanagement

Design and quality control of the oral health status examination in the German National Cohort (GNC)

Hintergrund Karies und Parodontitis sind weltweit hoch prävalente Erkrankungen. Durch ihre Erfassung im Rahmen der NAKO Gesundheitsstudie können Assoziationen zwischen oralen und systemischen Erkrankungen untersucht werden. Fragestellung In einer ersten Qualitätsanalyse zur Halbzeit der NAKO-Basiserhebung wird die Plausibilität der zahnmedizinischen Ergebnisse überprüft. Es werden Maßnahmen zur Verbesserung der Datenqualität vorgeschlagen. Material und Methoden Ein zahnmedizinisches Interview, eine Speichelprobengewinnung und eine Befunderhebung wurden durchgeführt. Im Rahmen der Level-1-Untersuchung wurden Zahn- und Prothesenanzahl erfasst. In der Level-2-Untersuchung wurden detaillierte parodontologische, kariologische und funktionelle Befunde erhoben. Alle Untersuchungen wurden von geschultem nichtzahnmedizinischen Personal durchgeführt. Es wurden Plausibilitätsprüfungen durchgeführt sowie Verteilungen deskriptiv dargestellt. Ergebnisse In die Analysen gingen Daten von 57.967 Interviewteilnehmer*innen, 56.913 Level-1- und 6295 Level-2-Teilnehmer*innen ein. Der Anteil fehlender Werte lag für die einzelnen Parameter der Level-1- und Level-2-Untersuchungen zwischen 0,02 % und 3,9 %. Die Parameter zeigten eine plausible Verteilung; vereinzelt wurden unplausible Werte beobachtet, z. B. beim horizontalen und vertikalen Überbiss (Overjet und Overbite). Anhand der Intraklassenkorrelationskoeffizienten wurden für die einzelnen Parameter Unterschiede zwischen regionalen Clustern, den Studienzentren und verschiedenen Untersucher*innen nachgewiesen. Diskussion Die bisherigen Ergebnisse bestätigten die Umsetzbarkeit des Studienprotokolls durch nichtzahnmedizinisches Personal und die erfolgreiche Integration in das Untersuchungsprogramm der NAKO Gesundheitsstudie. Die Studienzentren benötigen eine intensive zahnmedizinische Betreuung für das Qualitätsmanagement.Background Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated. Objectives The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality. Materials and methods A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level‑1 examination, the number of teeth and prostheses were recorded. As part of the level‑2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed. Results Analyses included data of 57,967 interview participants, 56,913 level‑1 participants and 6295 level‑2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners. Conclusions The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC’s overall assessment program. However, rigorous dental support of the study centres is required for quality management

GWAS analysis of handgrip and lower body strength in older adults in the CHARGE consortium

Summary Decline in muscle strength with aging is an important predictor of health trajectory in the elderly. Several factors, including genetics, are proposed contributors to variability in muscle strength. To identify genetic contributors to muscle strength, a meta‐analysis of genomewide association studies of handgrip was conducted. Grip strength was measured using a handheld dynamometer in 27 581 individuals of European descent over 65 years of age from 14 cohort studies. Genomewide association analysis was conducted on ~2.7 million imputed and genotyped variants (SNPs). Replication of the most significant findings was conducted using data from 6393 individuals from three cohorts. GWAS of lower body strength was also characterized in a subset of cohorts. Two genomewide significant (P‐value< 5 × 10−8) and 39 suggestive (P‐value< 5 × 10−5) associations were observed from meta‐analysis of the discovery cohorts. After meta‐analysis with replication cohorts, genomewide significant association was observed for rs752045 on chromosome 8 (β = 0.47, SE = 0.08, P‐value = 5.20 × 10−10). This SNP is mapped to an intergenic region and is located within an accessible chromatin region (DNase hypersensitivity site) in skeletal muscle myotubes differentiated from the human skeletal muscle myoblasts cell line. This locus alters a binding motif of the CCAAT/enhancer‐binding protein‐β (CEBPB) that is implicated in muscle repair mechanisms. GWAS of lower body strength did not yield significant results. A common genetic variant in a chromosomal region that regulates myotube differentiation and muscle repair may contribute to variability in grip strength in the elderly. Further studies are needed to uncover the mechanisms that link this genetic variant with muscle strength

GWAS analysis of handgrip and lower body strength in older adults in the CHARGE consortium.

Decline in muscle strength with aging is an important predictor of health trajectory in the elderly. Several factors, including genetics, are proposed contributors to variability in muscle strength. To identify genetic contributors to muscle strength, a meta-analysis of genomewide association studies of handgrip was conducted. Grip strength was measured using a handheld dynamometer in 27&nbsp;581 individuals of European descent over 65&nbsp;years of age from 14 cohort studies. Genomewide association analysis was conducted on ~2.7 million imputed and genotyped variants (SNPs). Replication of the most significant findings was conducted using data from 6393 individuals from three cohorts. GWAS of lower body strength was also characterized in a subset of cohorts. Two genomewide significant (P-value&lt; 5&nbsp;×&nbsp;10(-8) ) and 39 suggestive (P-value&lt; 5&nbsp;×&nbsp;10(-5) ) associations were observed from meta-analysis of the discovery cohorts. After meta-analysis with replication cohorts, genomewide significant association was observed for rs752045 on chromosome 8 (β&nbsp;=&nbsp;0.47, SE&nbsp;=&nbsp;0.08, P-value&nbsp;=&nbsp;5.20&nbsp;×&nbsp;10(-10) ). This SNP is mapped to an intergenic region and is located within an accessible chromatin region (DNase hypersensitivity site) in skeletal muscle myotubes differentiated from the human skeletal muscle myoblasts cell line. This locus alters a binding motif of the CCAAT/enhancer-binding protein-β (CEBPB) that is implicated in muscle repair mechanisms. GWAS of lower body strength did not yield significant results. A common genetic variant in a chromosomal region that regulates myotube differentiation and muscle repair may contribute to variability in grip strength in the elderly. Further studies are needed to uncover the mechanisms that link this genetic variant with muscle strength

Genome-wide analysis of dental caries and periodontitis combining clinical and self-reported data

Abstract Dental caries and periodontitis account for a vast burden of morbidity and healthcare spending, yet their genetic basis remains largely uncharacterized. Here, we identify self-reported dental disease proxies which have similar underlying genetic contributions to clinical disease measures and then combine these in a genome-wide association study meta-analysis, identifying 47 novel and conditionally-independent risk loci for dental caries. We show that the heritability of dental caries is enriched for conserved genomic regions and partially overlapping with a range of complex traits including smoking, education, personality traits and metabolic measures. Using cardio-metabolic traits as an example in Mendelian randomization analysis, we estimate causal relationships and provide evidence suggesting that the processes contributing to dental caries may have undesirable downstream effects on health