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Open Access Publications from the University of California

Scholarly Works (15 results)

  • Article
  • Peer Reviewed
Dermatology Online Journal, Volume 22, Issue 9 (2016)

BackgroundThe relationship between 25‐hydroxyvitamin D and different phenotypes of skin aging (e.g., wrinkles, pigmented spots, telangiectasia, perceived age) is unclear. We investigated the association between vitamin D levels and skin aging phenotypes in middle‐aged participants from the Rotterdam Study (RS) and Leiden Longevity Study (LLS).

MethodsStandardized facial photographs were taken of North‐European participants from the RS (N=3,831; 58.2% female, median age 66.5) and the LLS (N=661; 50.5% female, median age 63.1). Facial wrinkles, pigmented spots and telangiectasia (RS only) were quantified either digitally (RS) or by two independent dermatologists (LLS). Perceived age was graded by an average of 27 (range:20‐30) and 60 (range:59‐61) assessors in the RS and LLS respectively. The associations between vitamin D and these phenotypes (all standardized using Z‐scores) were investigated using multivariable linear regression analyses, adjusted for chronological age, sex, self‐reported UV‐exposure, season, smoking, body mass index and skin color, followed by meta‐analysis of the two cohorts.

ResultsHigher circulating 25‐hydroxyvitamin D was associated with more wrinkles (P‐value<0.0001) and a higher perceived age (P‐value<0.0001). However, there was no association between higher circulating 25‐hydroxyvitamin D and pigmented spots or telangiectasia (p‐values>0.05). Self‐reported UV‐exposure was associated with all four phenotypes. In RS, a light skin color was associated with more pigmented spots (P‐value<0.0001) and telangiectasia (P‐value<0.0001), but with less wrinkles (P‐value<0.0001).

ConclusionA higher circulating 25‐hydroxyvitamin D is associated with more facial wrinkles and a higher perceived age in middle‐aged and older individuals. However, although statistically adjusted for questionnaire‐based sun exposure, these two associations could be attributable to residual confounding.

    Cover page: Vitamin D and skin agingCreative Commons 'BY-NC-ND' version 4.0 license
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2022)

    Background

    Antithyroid antibodies increase the likelihood of developing overt hypothyroidism, but their clinical utility remains unclear. No large randomized controlled trial (RCT) has assessed whether older adults with subclinical hypothyroidism (SHypo) caused by autoimmune thyroid disease derive more benefits from levothyroxine treatment (LT4).

    Objective

    To determine whether older adults with SHypo and positive antibodies derive more clinical benefits from LT4 than those with negative antibodies.

    Methods

    We pooled individual participant data from two RCTs, Thyroid Hormone Replacement for Untreated Older Adults with Subclinical Hypothyroidism and IEMO 80+. Participants with persistent SHypo were randomly assigned to receive LT4 or placebo. We compared the effects of LT4 versus placebo in participants with and without anti-thyroid peroxidase (TPO) at baseline. The two primary outcomes were 1-year change in Hypothyroid Symptoms and Tiredness scores on the Thyroid-Related Quality-of-Life Patient-Reported Outcome Questionnaire.

    Results

    Among 660 participants (54% women) ≥65 years, 188 (28.5%) had positive anti-TPO. LT4 versus placebo on Hypothyroid Symptoms lead to an adjusted between-group difference of -2.07 (95% confidence interval: -6.04 to 1.90) for positive antibodies versus 0.89 (-1.76 to 3.54) for negative antibodies (p for interaction = 0.31). Similarly, there was no treatment effect modification by baseline antibody status for Tiredness scores-adjusted between-group difference 1.75 (-3.60 to 7.09) for positive antibodies versus 1.14 (-1.90 to 4.19) for negative antibodies (p for interaction = 0.98). Positive anti-TPO were not associated with better quality of life, improvement in handgrip strength, or fewer cardiovascular outcomes with levothyroxine treatment.

    Conclusions

    Among older adults with SHypo, positive antithyroid antibodies are not associated with more benefits on clinical outcomes with LT4.
      Cover page: Thyroid antibodies and levothyroxine effects in subclinical hypothyroidism: A pooled analysis of two randomized controlled trials
      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (2019)
      Brain lobar volumes are heritable but genetic studies are limited. We performed genome-wide association studies of frontal, occipital, parietal and temporal lobe volumes in 16,016 individuals, and replicated our findings in 8,789 individuals. We identified six genetic loci associated with specific lobar volumes independent of intracranial volume. Two loci, associated with occipital (6q22.32) and temporal lobe volume (12q14.3), were previously reported to associate with intracranial and hippocampal volume, respectively. We identified four loci previously unknown to affect brain volumes: 3q24 for parietal lobe volume, and 1q22, 4p16.3 and 14q23.1 for occipital lobe volume. The associated variants were located in regions enriched for histone modifications (DAAM1 and THBS3), or close to genes causing Mendelian brain-related diseases (ZIC4 and FGFRL1). No genetic overlap between lobar volumes and neurological or psychiatric diseases was observed. Our findings reveal part of the complex genetics underlying brain development and suggest a role for regulatory regions in determining brain volumes.
        Cover page: A genome-wide association study identifies genetic loci associated with specific lobar brain volumes
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2016)
        The growth hormone/insulin-like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF-related proteins including IGF-I and IGF-binding protein-3 (IGFBP-3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes, and cancer. Through genomewide association study of up to 30 884 adults of European ancestry from 21 studies, we confirmed and extended the list of previously identified loci associated with circulating IGF-I and IGFBP-3 concentrations (IGF1, IGFBP3, GCKR, TNS3, GHSR, FOXO3, ASXL2, NUBP2/IGFALS, SORCS2, and CELSR2). Significant sex interactions, which were characterized by different genotype-phenotype associations between men and women, were found only for associations of IGFBP-3 concentrations with SNPs at the loci IGFBP3 and SORCS2. Analyses of SNPs, gene expression, and protein levels suggested that interplay between IGFBP3 and genes within the NUBP2 locus (IGFALS and HAGH) may affect circulating IGF-I and IGFBP-3 concentrations. The IGF-I-decreasing allele of SNP rs934073, which is an eQTL of ASXL2, was associated with lower adiposity and higher likelihood of survival beyond 90 years. The known longevity-associated variant rs2153960 (FOXO3) was observed to be a genomewide significant SNP for IGF-I concentrations. Bioinformatics analysis suggested enrichment of putative regulatory elements among these IGF-I- and IGFBP-3-associated loci, particularly of rs646776 at CELSR2. In conclusion, this study identified several loci associated with circulating IGF-I and IGFBP-3 concentrations and provides clues to the potential role of the IGF axis in mediating effects of known (FOXO3) and novel (ASXL2) longevity-associated loci.
          Cover page: Genomewide meta‐analysis identifies loci associated with IGF‐I and IGFBP‐3 levels with impact on age‐related traits
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2017)

          Background

          Increased heart rate and a prolonged QT interval are important risk factors for cardiovascular morbidity and mortality, and can be influenced by the use of various medications, including tricyclic/tetracyclic antidepressants (TCAs). We aim to identify genetic loci that modify the association between TCA use and RR and QT intervals.

          Methods and results

          We conducted race/ethnic-specific genome-wide interaction analyses (with HapMap phase II imputed reference panel imputation) of TCAs and resting RR and QT intervals in cohorts of European (n=45 706; n=1417 TCA users), African (n=10 235; n=296 TCA users) and Hispanic/Latino (n=13 808; n=147 TCA users) ancestry, adjusted for clinical covariates. Among the populations of European ancestry, two genome-wide significant loci were identified for RR interval: rs6737205 in BRE (β=56.3, pinteraction=3.9e-9) and rs9830388 in UBE2E2 (β=25.2, pinteraction=1.7e-8). In Hispanic/Latino cohorts, rs2291477 in TGFBR3 significantly modified the association between TCAs and QT intervals (β=9.3, pinteraction=2.55e-8). In the meta-analyses of the other ethnicities, these loci either were excluded from the meta-analyses (as part of quality control), or their effects did not reach the level of nominal statistical significance (pinteraction>0.05). No new variants were identified in these ethnicities. No additional loci were identified after inverse-variance-weighted meta-analysis of the three ancestries.

          Conclusions

          Among Europeans, TCA interactions with variants in BRE and UBE2E2 were identified in relation to RR intervals. Among Hispanic/Latinos, variants in TGFBR3 modified the relation between TCAs and QT intervals. Future studies are required to confirm our results.
            Cover page: A genome-wide interaction analysis of tricyclic/tetracyclic antidepressants and RR and QT intervals: a pharmacogenomics study from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2019)
            Human longevity is heritable, but genome-wide association (GWA) studies have had limited success. Here, we perform two meta-analyses of GWA studies of a rigorous longevity phenotype definition including 11,262/3484 cases surviving at or beyond the age corresponding to the 90th/99th survival percentile, respectively, and 25,483 controls whose age at death or at last contact was at or below the age corresponding to the 60th survival percentile. Consistent with previous reports, rs429358 (apolipoprotein E (ApoE) ε4) is associated with lower odds of surviving to the 90th and 99th percentile age, while rs7412 (ApoE ε2) shows the opposite. Moreover, rs7676745, located near GPR78, associates with lower odds of surviving to the 90th percentile age. Gene-level association analysis reveals a role for tissue-specific expression of multiple genes in longevity. Finally, genetic correlation of the longevity GWA results with that of several disease-related phenotypes points to a shared genetic architecture between health and longevity.
              Cover page: A meta-analysis of genome-wide association studies identifies multiple longevity genes
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2021)
              Long and short sleep duration are associated with elevated blood pressure (BP), possibly through effects on molecular pathways that influence neuroendocrine and vascular systems. To gain new insights into the genetic basis of sleep-related BP variation, we performed genome-wide gene by short or long sleep duration interaction analyses on four BP traits (systolic BP, diastolic BP, mean arterial pressure, and pulse pressure) across five ancestry groups in two stages using 2 degree of freedom (df) joint test followed by 1df test of interaction effects. Primary multi-ancestry analysis in 62,969 individuals in stage 1 identified three novel gene by sleep interactions that were replicated in an additional 59,296 individuals in stage 2 (stage 1 + 2 Pjoint < 5 × 10-8), including rs7955964 (FIGNL2/ANKRD33) that increases BP among long sleepers, and rs73493041 (SNORA26/C9orf170) and rs10406644 (KCTD15/LSM14A) that increase BP among short sleepers (Pint < 5 × 10-8). Secondary ancestry-specific analysis identified another novel gene by long sleep interaction at rs111887471 (TRPC3/KIAA1109) in individuals of African ancestry (Pint = 2 × 10-6). Combined stage 1 and 2 analyses additionally identified significant gene by long sleep interactions at 10 loci including MKLN1 and RGL3/ELAVL3 previously associated with BP, and significant gene by short sleep interactions at 10 loci including C2orf43 previously associated with BP (Pint < 10-3). 2df test also identified novel loci for BP after modeling sleep that has known functions in sleep-wake regulation, nervous and cardiometabolic systems. This study indicates that sleep and primary mechanisms regulating BP may interact to elevate BP level, suggesting novel insights into sleep-related BP regulation.
                Cover page: Multi-ancestry genome-wide gene–sleep interactions identify novel loci for blood pressure
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2017)
                Genome-wide association studies have identified hundreds of genetic variants associated with blood pressure (BP), but sequence variation accounts for a small fraction of the phenotypic variance. Epigenetic changes may alter the expression of genes involved in BP regulation and explain part of the missing heritability. We therefore conducted a two-stage meta-analysis of the cross-sectional associations of systolic and diastolic BP with blood-derived genome-wide DNA methylation measured on the Infinium HumanMethylation450 BeadChip in 17,010 individuals of European, African American, and Hispanic ancestry. Of 31 discovery-stage cytosine-phosphate-guanine (CpG) dinucleotides, 13 replicated after Bonferroni correction (discovery: N = 9,828, p < 1.0 × 10-7; replication: N = 7,182, p < 1.6 × 10-3). The replicated methylation sites are heritable (h2 > 30%) and independent of known BP genetic variants, explaining an additional 1.4% and 2.0% of the interindividual variation in systolic and diastolic BP, respectively. Bidirectional Mendelian randomization among up to 4,513 individuals of European ancestry from 4 cohorts suggested that methylation at cg08035323 (TAF1B-YWHAQ) influences BP, while BP influences methylation at cg00533891 (ZMIZ1), cg00574958 (CPT1A), and cg02711608 (SLC1A5). Gene expression analyses further identified six genes (TSPAN2, SLC7A11, UNC93B1, CPT1A, PTMS, and LPCAT3) with evidence of triangular associations between methylation, gene expression, and BP. Additional integrative Mendelian randomization analyses of gene expression and DNA methylation suggested that the expression of TSPAN2 is a putative mediator of association between DNA methylation at cg23999170 and BP. These findings suggest that heritable DNA methylation plays a role in regulating BP independently of previously known genetic variants.
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2016)
                  Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
                    Cover page: Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2019)
                    Both short and long sleep are associated with an adverse lipid profile, likely through different biological pathways. To elucidate the biology of sleep-associated adverse lipid profile, we conduct multi-ancestry genome-wide sleep-SNP interaction analyses on three lipid traits (HDL-c, LDL-c and triglycerides). In the total study sample (discovery + replication) of 126,926 individuals from 5 different ancestry groups, when considering either long or short total sleep time interactions in joint analyses, we identify 49 previously unreported lipid loci, and 10 additional previously unreported lipid loci in a restricted sample of European-ancestry cohorts. In addition, we identify new gene-sleep interactions for known lipid loci such as LPL and PCSK9. The previously unreported lipid loci have a modest explained variance in lipid levels: most notable, gene-short-sleep interactions explain 4.25% of the variance in triglyceride level. Collectively, these findings contribute to our understanding of the biological mechanisms involved in sleep-associated adverse lipid profiles.
                      Cover page: Multi-ancestry sleep-by-SNP interaction analysis in 126,926 individuals reveals lipid loci stratified by sleep duration
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