Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly with limited therapeutic options. Here, we report on a study of >12 million variants including 163,714 directly genotyped, most rare, protein-altering variant. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5×10–8) distributed across 34 loci. While wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first signal specific to wet AMD, near MMP9 (difference-P = 4.1×10–10). Very rare coding variants (frequency < 0.1%) in CFH, CFI, and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate that applying the approach systematically to detect new loci requires extremely large sample sizes.

SUMMARY Relatively little is known about the interaction between genes and environment in the complex etiology of age-related macular degeneration (AMD). This study aimed to identify novel factors associated with AMD by analyzing gene-smoking interactions in a genome-wide association study of 1207 AMD cases and 686 controls of Caucasian background with genotype data on 668,238 single nucleotide polymorphisms (SNPs) after quality control. Participants’ history of smoking at least 100 cigarettes lifetime was determined by a self-administered questionnaire. SNP associations modeled the effect of the minor allele additively on AMD using logistic regression, with adjustment for age, sex, and ever/never smoking. Joint effects of SNPs and smoking were examined comparing a null model containing only age, sex, and smoking against an extended model including genotypic and interaction terms. Genome-wide significant main effects were detected at three known AMD loci: CFH (P=7.51×10−30), ARMS2 (P=1.94×10−23), and RDBP/CFB/C2 (P=4.37×10−10), while joint effects analysis revealed three genomic regions with P<10−5. Analyses stratified by smoking found genetic associations largely restricted to non-smokers, with one notable exception: the chromosome 18q22.1 intergenic SNP rs17073641 (between SERPINB8 and CDH7), more strongly associated in non-smokers (OR=0.57, P=2.73×10−5), with an inverse association among smokers (OR=1.42, P=0.00228), suggesting that smoking modifies the effect of some genetic polymorphisms on AMD risk.

IMPORTANCE Advanced age-related macular degeneration (AMD) is a leading cause of blindness in Western countries. Causal, modifiable risk factors need to be identified to develop preventive measures for advanced AMD.OBJECTIVE To assess whether smoking, alcohol consumption, blood pressure, body mass index, and glycemic traits are associated with increased risk of advanced AMD. DESIGN, SETTING, PARTICIPANTSThis study used 2-sample mendelian randomization. Genetic instruments composed of variants associated with risk factors at genome-wide significance (P < 5 × 10 −8 ) were obtained from published genome-wide association studies. Summary-level statistics for these instruments were obtained for advanced AMD from the International AMD Genomics Consortium 2016 data set, which consisted of 16 144 individuals with AMD and 17 832 control individuals. Data were analyzed from July 2020 to September 2021.EXPOSURES Smoking initiation, smoking cessation, lifetime smoking, age at smoking initiation, alcoholic drinks per week, body mass index, systolic and diastolic blood pressure, type 2 diabetes, glycated hemoglobin, fasting glucose, and fasting insulin. MAIN OUTCOMES AND MEASURESAdvanced AMD and its subtypes, geographic atrophy (GA), and neovascular AMD.RESULTS A 1-SD increase in logodds of genetically predicted smoking initiation was associated with higher risk of advanced AMD (odds ratio [OR], 1.26; 95% CI, 1.13-1.40; P < .001), while a 1-SD increase in logodds of genetically predicted smoking cessation (former vs current smoking) was associated with lower risk of advanced AMD (OR, 0.66; 95% CI, 0.50-0.87; P = .003). Genetically predicted increased lifetime smoking was associated with increased risk of advanced AMD (OR per 1-SD increase in lifetime smoking behavior, 1.32; 95% CI, 1.09-1.59; P = .004). Genetically predicted alcohol consumption was associated with higher risk of GA (OR per 1-SD increase of log-transformed alcoholic drinks per week, 2.70; 95% CI, 1.48-4.94; P = .001). There was insufficient evidence to suggest that genetically predicted blood pressure, body mass index, and glycemic traits were associated with advanced AMD. CONCLUSIONS AND RELEVANCEThis study provides genetic evidence that increased alcohol intake may be a causal risk factor for GA. As there are currently no known treatments for GA, this finding has important public health implications. These results also support previous observational studies associating smoking behavior with risk of advanced AMD, thus reinforcing existing public health messages regarding the risk of blindness associated with smoking.

Various hand hygiene techniques have been recommended by sanitarians. In the USA, the National Restaurant Association (NRA) ServSafe® program guidelines include a recommended hand washing regime. The ServSafe regime was compared to rinsing with warm and cool water and no washing/rinsing for bare hands and gloves after exposure to ground beef (approximately 106 cells/g) or liquid solution (approximately 106 cells/mL) contaminated with an ampicillin‐resistant Escherichia coli JM 109 strain. The efficacy of alcohol‐based hand sanitizers to replace hand washing was also evaluated. ServSafe, warm water rinse and cool water rinse reduced E. coli cells on hands by 98.0, 64.4 and 42.8% log10 cfu/mL, resulting in <1, 1.4, and 2,1 log10 cfu/mL E. coli on hands, respectively, from 3.6 log10 cfu/mL on unwashed hands. When vinyl food service gloves were worn during the hand washing treatments, gloves retained more bacteria than when only hands were rinsed or washed. From 2.9 to 3.4 log10 cfu/mL remained on hands when ethanol‐based sanitizers were used instead of hand washing. Of all hand washing treatments tested in these experiments, the US NRA recommended method was most effective (P < 0.05) in removing E. coli from hands and the levels remaining after this method were below the threshold of detection (<10 cfu/hand).

Avoiding disease, maintaining physical and cognitive function, and continued social engagement in long-lived individuals describe successful aging (SA). Mitochondrial lineages described by patterns of common genetic variants (“haplogroups”) have been associated with increased longevity in different populations. We investigated the influence of mitochondrial haplogroups on SA in an Amish community sample. Cognitively intact volunteers aged ≥80 (n=261) were enrolled in a door-to-door survey of Amish communities in Indiana and Ohio. Individuals scoring in the top third for lower extremity function, needing little assistance with self-care tasks, having no depression symptoms, and expressing high life satisfaction were considered SA (n=74). The remainder (n=187) were retained as controls. These individuals descend from 51 matrilines in a single 13 generation pedigree. Mitochondrial haplogroups were assigned using the 10 mitochondrial single nucleotide polymorphisms (mtSNPs) defining the nine most common European haplogroups. An additional 17 mtSNPs from a genome-wide association panel were also investigated. Associations between haplogroups, mtSNPs, and SA were determined by logistic regression models accounting for sex, age, body mass index, and matriline via generalized estimating equations. SA cases were more likely to carry Haplogroup X (OR=7.56, p=0.0015), and less likely to carry Haplogroup J (OR=0.40, p=0.0003). Our results represent a novel association of Haplogroup X with SA and suggest that variants in the mitochondrial genome may promote maintenance of both physical and cognitive function in older adults.