Association of time outdoors and patterns of light exposure with myopia in children.

BACKGROUND/AIMS: To evaluate the association of reported time outdoors and light exposure patterns with myopia among children aged 9 years from the Growing Up in Singapore Towards Healthy Outcomes birth cohort. METHODS: We assessed reported time outdoors (min/day), light exposure patterns and outdoor activities of children aged 9 years (n=483) with a questionnaire, the FitSight watch and a 7-day activity diary. Light levels, the duration, timing and frequency of light exposure were assessed. Cycloplegic spherical equivalent (SE), myopia (SE≤-0.5 D) and axial length (AL) of paired eyes were analysed using generalised estimating equations. RESULTS: In this study, 483 (966 eyes) multiethnic children (50.0% boys, 59.8% Chinese, 42.2% myopic) were included. Reported time outdoors (mean±SD) was 100±93 min/day, and average light levels were 458±228 lux. Of the total duration children spent at light levels of ≥1000 lux (37±19 min/day), 76% were spent below 5000 lux. Peak light exposure occurred at mid-day. Children had 1.7±1.0 light exposure episodes/day. Common outdoor activities were walks, neighbourhood play and swimming. Greater reported time outdoors was associated with lower odds of myopia (OR=0.82, 95% CI 0.70 to 0.95/hour increase daily; p=0.009). Light levels, timing and frequency of light exposures were not associated with myopia, SE or AL (p>0.05). CONCLUSION: Reported time outdoors, light levels and number of light exposure episodes were low among Singaporean children aged 9 years. Reported time outdoors was protective against myopia but not light levels or specific light measures. A multipronged approach to increase time outdoors is recommended in the combat against the myopia epidemic.

Systematic Review and Meta-Analysis on the Impact of COVID-19 Pandemic-Related Lifestyle on Myopia.

PURPOSE: To conduct a systematic review and meta-analysis to assess the effects of coronavirus disease 2019 (COVID-19) pandemic-related lifestyle on myopia outcomes in children to young adults. METHODS: A systematic search was conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases (with manual searching of reference lists of reviews). Studies included assessed changes in myopia-related outcomes (cycloplegic refraction) during COVID and pre-COVID. Of 367 articles identified, 7 (6 prospective cohorts; 1 repeated cross-sectional study) comprising 6327 participants aged 6 to 17 were included. Quality appraisals were performed with Joanna Briggs Institute Critical Appraisal Checklists. Pooled differences in annualized myopic shifts or mean spherical equivalent (SE) during COVID and pre-COVID were obtained from random-effects models. RESULTS: In all 7 studies, SE moved toward a myopic direction during COVID (vs pre-COVID), where 5 reported significantly faster myopic shifts [difference in means of changes: -1.20 to -0.35 diopters per year, [D/y]; pooled estimate: -0.73 D/y; 95% confidence interval (CI): -0.96, -0.50; P<0.001], and 2 reported significantly more myopic SE (difference in means: -0.72 to -0.44 D/y; pooled estimate: -0.54 D/y; 95% CI: -0.80, -0.28; P<0.001). Three studies reported higher myopia (SE ≤-0.50 D) incidence (2.0- to 2.6-fold increase) during COVID versus pre-COVID. Of studies assessing lifestyle changes, all 4 reported lower time outdoors (pre-COVID vs during COVID: 1.1-1.8 vs 0.4-1.0 hours per day, [h/d]), and 3 reported higher screen time (pre-COVID vs during COVID: 0.7-2.8 vs 2.4-6.9 h/d). CONCLUSIONS: This review suggests more myopic SE shifts during COVID (vs pre-COVID) in participants aged 6 to 17. COVID-19 restrictions may have worsened SE shifts, and lifting of restrictions may lessen this effect. Evaluations of the long-term effects of the pandemic lifestyle on myopia onset and progression in large studies are warranted to confirm these findings.

Sleep Patterns and Myopia Among School-Aged Children in Singapore.

Purpose: To evaluate the associations of sleep factors with myopia, spherical equivalent (SE), and axial length (AL) in elementary school-aged children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort. Methods: This cross-sectional study included multi-ethnic children who participated in the GUSTO prospective birth cohort and were delivered in two major tertiary hospitals in Singapore (2009-2010). Sleep factors and myopia outcomes were assessed at the 8- and 9-year study visits, respectively. Parent-reported sleep quality was assessed with the Children's Sleep Habits Questionnaire (CSHQ) total scores. Additionally, each child's sleep duration, timing (bedtime; waketime), and the consistency of sleep duration or timing (i.e., the difference between weekends and weekdays) were parent-reported. Outcomes included cycloplegic SE, myopia (SE ≤ -0.5 D) and AL. Eye measurements from both eyes were included in the analyses. Multivariable linear or logistic regression with Generalized Estimating Equations were used to account for the correlation between paired eyes and confounders in the associations of sleep factors at age 8 and myopia at age 9. Results: A total of 572 multi-ethnic children (49.5% boys; 56.1% Chinese) aged 9 years were included in the analyses. Overall, 37.3% of eyes were myopic. Children reported a mean total CSHQ score of 46 [standard deviation (SD) = 6]. The mean duration of sleep was 9.2 (SD = 1.0) hours per day (h/day), with 59.9% of children reporting sufficient sleep (≥9 h/day) based on guidelines recommended by the National Sleep Foundation, USA. The mean bedtime and wake time were 22:00 (SD = 00:53) and 07:08 (SD = 00:55), respectively. In multivariable regression models, total CSHQ scores, the duration of sleep, bedtime and wake time were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all), adjusting for gender, ethnicity, time outdoors, near-work, parental myopia, maternal education levels (and additionally the child's height when the outcome was AL). Similarly, the consistency of both the duration and timing of sleep (across weekends and weekdays) were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all). Conclusion: In this cross-sectional study, sleep quality, duration, timing, and the consistency of specific sleep factors were not independently associated with myopia, SE, or AL among elementary school-aged children in Singapore. Large longitudinal studies are warranted to corroborate these results.

Dietary intake and associations with myopia in Singapore children.

PURPOSE: To evaluate associations of dietary factors with myopia, spherical equivalent refractive error (SE) and axial length (AL) in children at age 9 from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort. METHODS: We included 467 multi-ethnic children (933 eyes) who participated in the GUSTO prospective birth cohort and were delivered in two major hospitals in Singapore (2009-2010). At the 9-year visit, we assessed the 6-year incidence of myopia (between ages 3 to 9), cycloplegic SE and AL in children without myopia (SE ≤ -0.5 D in either eye) at the 3-year visit. Using a validated 112-item food frequency questionnaire, parents reported each child's average daily intake of dietary factors (nutrients and food groups) in the past month. Paired eyes were analysed using Generalised Estimating Equations with multivariable logistic or linear regression. Bonferroni corrections were applied, correcting for multiple comparisons between the 13 nutrients (p < 0.004) or 8 food groups (p < 0.006) and each outcome. RESULTS: In children aged 9 years (51.0% boys; 56.3% Chinese), the 6-year incidence of myopia was 35.5%. Overall, the mean (SD) SE and AL were -0.3 (1.7) D and 23.4 (1.0) mm, respectively. In multivariable regression, macronutrients or micronutrients were not associated with incident myopia (p ≥ 0.004 for all), adjusting for total energy, gender, ethnicity, time outdoors, near-work and the number of myopic parents (additionally child's height for outcome AL). Similarly, all food groups (including refined grains, sugar-sweetened beverages, protein foods, fruits and vegetables) were not associated with incident myopia (p ≥ 0.006 for all). Additionally, none of the nutrients (p ≥ 0.004 for all) or food groups (p ≥ 0.006 for all) were associated with SE or AL. CONCLUSIONS: Our study findings of no significant association between specific nutrients or food groups and incident myopia or SE or AL suggest that diet may not be associated with myopia in children aged 9 years. Well-conducted prospective studies in other populations may clarify the association.

Tetra-primer ARMS-PCR identifies the novel genetic variations of bovine HNF-4α gene associating with growth traits.

Hepatocyte nuclear factor-4α (HNF-4α), a member of the hepatocyte nuclear factor family, plays an important role in regulating the expression of genes involved in the development, differentiation and normal function of liver and pancreatic ß cells, as well as the maintenance of glucose homeostasis. Tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) is a new method offering fast detection and extreme simplicity at a negligible cost for SNP genotyping. In this paper, we characterize the polymorphisms of the bovine HNF-4α gene in three Chinese indigenous cattle breeds (n=660). Six novel SNPs were identified including 1 mutation in the coding region and others in introns. The statistical analyses indicated that 4 SNPs (g.T53729C, g.A53861G, g.A65188C and g.T65444C) affected growth traits markedly (P<0.05) in Qinchuan cattle (2 years after birth). Besides, haplotypes involving these 4 SNP sites in the bovine HNF-4α gene were identified and their effects on growth traits were also analyzed. The results showed that haplotypes 2, 7, 9 and 11 were predominant and accounted for 73.2%, 59.6%, and 67.1% in Qinchuan, Nanyang and Jiaxian cattle breeds, respectively. Hap9 (TAAT) was extremely predominant in all test populations, which suggested that individuals with Hap9 were more adapted to the environment. Furthermore, 4 combined haplotypes were constructed to guarantee the reliability of analysis results in Qinchuan cattle. There were also significant differences in body length (P<0.05). These findings will benefit for the application of DNA marker related to the growth traits on marker-assisted selection (MAS), and improve the performance of beef cattle.

The novel coding region SNPs of PPARGC1A gene and their associations with growth traits in Chinese native cattle.

The peroxisome proliferator-activated receptor gamma coactivator-1 alpha protein, encoded by the PPARGC1A gene, is a metabolic switch, which transcriptionally activates a complex pathway of mitochondrial biogenesis, lipid and glucose metabolism. Three SNPs (exon 3 c.396G>A, intron 9 c.1892 + 19C>T and exon 10 c.1971C>T) were found and identified in three Chinese native cattle breeds by PCR-SSCP, PCR-RFLP and DNA sequencing methods. All three populations had a low genetic diversity at SNP396 locus (PIC <0.25) while possessed a moderate genetic diversity at SNP1892 locus (0.25 < PIC < 0.5). Association study indicated that the synonymous mutation c.396G>A significantly associated with body weight and average daily gain in Nanyang cattle at the adult age (P < 0.05). Our investigation will not only extend the spectrum of genetic variation of bovine PPARGC1A gene, but also provide useful information for the marker assisted selection in beef cattle breeding program.

Association analysis of bovine Foxa2 gene single sequence variant and haplotype combinations with growth traits in Chinese cattle.

Forkhead box A2 (Foxa2) has been recognized as one of the most potent transcriptional activators that is implicated in the control of feeding behavior and energy homeostasis. However, similar researches about the effects of genetic variations of Foxa2 gene on growth traits are lacking. Therefore, this study detected Foxa2 gene polymorphisms by DNA pool sequencing, PCR-RFLP and PCR-ACRS methods in 822 individuals from three Chinese cattle breeds. The results showed that four sequence variants (SVs) were screened, including two mutations (SV1, g. 7005 C>T and SV2, g. 7044 C>G) in intron 4, one mutation (SV3, g. 8449 A>G) in exon 5 and one mutation (SV4, g. 8537 T>C) in the 3'UTR. Notably, association analysis of the single mutations with growth traits in total individuals (at 24months) revealed that significant statistical difference was found in four SVs, and SV4 locus was highly significantly associated with growth traits throughout all three breeds (P<0.05 or P<0.01). Meanwhile, haplotype combination CCCCAGTC also indicated remarkably associated to better chest girth and body weight in Jiaxian Red cattle (P<0.05). We herein described a comprehensive study on the variability of bovine Foxa2 gene that was predictive of molecular markers in cattle breeding for the first time.

Haplotype combination of polymorphisms in the ADIPOQ gene promoter is associated with growth traits in Qinchuan cattle.

Adiponectin modulates lipid and glucose metabolism in adipose tissues and is also related to bone metabolism. Polymorphisms in the ADIPOQ gene likely have an impact on growth traits in cattle. In this study, we examined the relationship between ADIPOQ polymorphisms and body measurement parameters in Chinese beef cattle. First, we sequenced ADIPOQ and 1.2 kb of DNA upstream of its promoter, and we found 14 polymorphisms. With the luciferase reporter assay, we showed that the two polymorphisms SNP PR_-135 A>G and PR_-68 G>C, which are located in the core region of promoter, influence promoter activity of ADIPOQ. Second, we identified three haplotypes involved in these two polymorphic sites: A (A-135/C-68), B (A-135/G-68), and C (G-135/G-68). Haplotypes B and C are major haplotypes in five Chinese populations of cattle (Qinchuan, Nanyang, Jiaxian, Hazakh, and Chinese Holstein). We studied the effects of these three haplotypes on body measurements, gene expression, and promoter activity, and we found that the genotypes are associated with body measurement parameters in Qinchuan cattle. Individuals with genotype BC (AG/GG) had significantly higher body height and heart girth than others, and this result may be interpreted by the following two observations. The promoter activity with haplotype B (A/G) is significantly higher than those with A (A/C) and C (G/G) in driving reporter gene transcription; the ADIPOQ mRNA level in cattle with genotype BC (AG/GG) is relatively lower than that in cattle with genotype BB (AA/GG).

Identification and profiling of conserved and novel microRNAs from Chinese Qinchuan bovine longissimus thoracis.

BACKGROUND: MicroRNAs (miRNAs) are a family of ~22 nucleotide small RNA molecules that regulate gene expression by fully or partially binding to their complementary sequences. Recently, a large number of miRNAs and their expression patterns have been identified in various species. However, to date no miRNAs have been reported to modulate muscle development in beef cattle. RESULTS: Total RNAs from the Chinese Qinchuan bovine longissimus thoracis at fetal and adult stages were used to construct small RNA libraries for Solexa SBS technology sequencing. A total of 15,454,182 clean reads were obtained from the fetal bovine library and 13,558,164 clean reads from the adult bovine library. In total, 521 miRNAs including 104 novel miRNA candidates were identified. Furthermore, the nucleotide bias, base edit and family of the known miRNAs were also analyzed. Based on stem-loop qPCR, 25 high-read miRNAs were detected, and the results showed that bta-miRNA-206, miRNA-1, miRNA-133, miRNAn12, and miRNAn17 were highly expressed in muscle-related tissue or organs, suggesting that these miRNAs may play a role in the development of bovine muscle tissues. CONCLUSIONS: This study confirmed the authenticity of 417 known miRNAs, discovered 104 novel miRNAs in bos taurus, and identified five muscle-specific miRNAs. The identification of novel miRNAs significantly expanded the repertoire of bovine miRNAs and could contribute to further studies on the muscle development of cattle.

SNP identification in FBXO32 gene and their associations with growth traits in cattle.

The F-box protein 32 (FBXO32), also known as Atrogin-1, is one of the four subunits of the ubiquitin protein ligase complex. FBXO32 has been previously shown to be involved in regulation of initiation and development of muscle mass. In the present study, we investigated the polymorphism of FBXO32 gene in 1313 cattle from seven bovine breeds using DNA sequencing, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-based amplification-created restriction site (PCR-ACRS) methods. Four novel single nucleotide polymorphisms (SNPs) were identified within bovine FBXO32, and were deposited in the GenBank database. The association studies between these four SNPs and growth traits were performed in NanYang cattle. Notably, the SNPs ss411628932 and ss411628936 were shown to be significantly associated with body length of 24-month-old NanYang cattle. Based on the above four SNPs, 16 haplotypes were identified. The main haplotype was AATA, which occurred at a frequency of more than 40%. Additionally, phylogenetic analysis showed that geographical distance was essential to gene flow among seven cattle breeds. Indigenous bovine breeds displayed genetic difference in comparison to hybrid bovine breeds that have foreign origins. We herein describe for the first time a comprehensive study on the variability of bovine FBXO32 gene that is predictive of genetic potential for body length phenotype.

Exploring polymorphisms and potential application roles of the bovine Nfix gene in breeding.

The aim of this study was to detect mutations of the nuclear factor I/X (Nfix) gene and examine the association of its polymorphisms with growth traits in cattle. Six sequence variants (SVs) including five single-nucleotide mutations and an indel with multiple alleles were detected, among which four polymorphisms within the Nfix gene were identified in 1159 individuals of five cattle breeds by sequencing and forced PCR-RFLP methods. The results of haplotype analysis showed 14 haplotypes within the breeds. Three haplotypes were shared by the five cattle breeds. Hap1 (ACAI) was extremely predominant in all test populations, which suggested that individuals with Hap1 (ACAI) were more adapted to the steppe environment. Association analysis in Nanyang cattle showed that two SVs of the Nfix gene were significantly associated with growth traits at different ages. In addition, the locations of the SVs showed that the 3' terminal of the bovine Nfix gene was unstable. Combining this instability with its characteristic of multiple alternative splicing, we conjectured that some SVs might have a relationship with the formation of the splices through which growth traits are modulated. This study will provide useful information for the selection and detection of multiple forms of alternative splicing of the bovine Nfix gene.

Two novel cSNPs of weaver gene in Chinese indigenous goat and their associations with milk yield.

Weaver gene plays an essential physiological role in the function of many organs, including brain, heart, kidney and endocrine cells, and also in the regulation of insulin secretion by glucose and/or neurotransmitters. Thus, weaver gene is an important potential candidate gene effecting on performance traits. The objective of this study was to detect the genetic variation of five loci within weaver gene by PCR-SSCP, DNA sequencing and forced PCR-RFLP methods in 1,019 Chinese indigenous goats. Two novel coding SNPs (XM_598993:m.864G>A; XM_598993:m.1224T>A) locating on P3 and P4 loci were identified and detected by MluI and AsuII forced PCR-RFLP, respectively. In the MluI analysis, the frequencies of goat MluI-A allele in the analyzed populations were 0.226, 0.248, 0.096 and 0.088 for XNSN, GZ, SBWC and XJWC, respectively. Genotypic frequencies were found to be significantly different in four breeds (chi2 = 75.842, df = 6, P < 0.001); In the AsuII analysis, the frequencies of goat AsuII-A allele in the analyzed populations were 0.584, 0.441, 0.073 and 0.063 for XNSN, GZ, SBWC and XJWC, respectively. Genotypic frequencies were found to be significantly different among four breeds (chi2 = 399.464, df = 6, P < 0.001). The frequencies of allele MluI-A and AsuII-A in XNSN and GZ populations were significantly higher than those of SBWC and XJWC goats. Association analysis with adjusted milk yield in the XNSN breed indicated that the animals with AsuII-AA genotype owned significantly higher adjusted milk yield than the ones with AsuII-TT genotype in the second lactation (P < 0.05). The observation suggested that the allele "AsuII-A" had the positive effects on adjusted milk yield in the second lactation.