Prevalence, incidence, and risk factors for myopia among urban and rural children in southern China: protocol for a school-based cohort study
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ABSTRACT: Introduction
Myopia is the common cause of reduced uncorrected visual acuity among school-age children. It is more prevalent in urban than in rural areas. Although many myopia studies have focused on the effect of urbanisation, it remains unclear how visual experience in urban regions could affect childhood myopia. This study aims to investigate the incidence and prevalence of myopia among school-age children in urban and rural settings, thereby identifying the environmental factors that affect the onset and progression of myopia. Methods and analysis
A school-based cohort study will be conducted. We will enroll all first-grade students from an urban (10 primary schools) and a rural (10 primary schools) regions of Zhaoqing city, China. Over 3-year follow-up period, students will receive detailed eye examinations annually and complete questionnaires about living habits and environment. In a 5% random subsample of the cohort, physical activity, light intensity and eye-tracking data will be obtained using wearable devices, and high-resolution macular images will be obtained by optical coherence tomography (OCT). The primary outcome is incident myopia, defined as myopia (spherical equivalent refractive of at least −0.5D) detected during follow-up among those without myopia at baseline. Ethics and dissemination
Ethics approval was obtained from the ethics committee of the Zhongshan Ophthalmic Center (number: 2019KYPJ171). Study findings will be published in a peer-reviewed journal. Trial registration number
NCT04219228.
SUBMITTER: Chen X
PROVIDER: S-EPMC8573650 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:The prevalence of myopia has increased rapidly worldwide over the past few decades. The aim of this study was to evaluate the prevalence and associated risk factors for myopia in elementary and junior high school students in Chia-Yi, Taiwan. METHODS:We included 5417 students in total from Grade 1-6 (n?=?4763) and Grade 7-9 (n?=?654) from Chia Yi County in this population-based study. The students underwent noncycloplegic autorefractometry and an interview with a structured questionnaire. RESULTS:For this study population, the prevalence of myopia and high myopia was 42.0 and 2.0%, respectively, revealing a statistically significant increase with increasing age (p?<?0.05). Junior high school students (aged 13-15) showed a greater prevalence of myopia than elementary school students (aged 7-12) (55.8% vs. 40.1%, respectively, p?<?0.001). Multiple logistic regression analysis showed that associated factors of myopia were body height (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.05-1.06), body mass index (OR: 0.98, 95% CI: 0.96-1.00), and ocular alignment (horizontal heterophoria vs. orthophoria, OR: 2.37, 95% CI: 2.08-2.70; tropia vs. orthophoria, OR: 1.94, 95% CI: 1.50-2.52) for elementary school students, whereas in junior high school students, they included body height (OR: 1.02, 95% CI: 1.01-1.04) and ocular alignment (heterophoria vs. orthophoria, OR: 2.20, 95% CI: 1.56-3.10). CONCLUSIONS:This study provided epidemiological data on myopia in rural school students in Chia-Yi, Taiwan, and demonstrated the association between heterophoria and myopia. Correction of refractive errors in the students remained a challenge.
| S-EPMC7405435 | biostudies-literature
Project description:Rural-to-urban migration, which has achieved a huge scale during China's economic reform, is a potential risk factor for the mental health of migrant children. To test this hypothesis, this study assessed the mental health status of rural-to-urban migrant children. Guided by Andersen's behavioral model, the study explored the risk factors associated with mental health. The study recruited 1182 fifth/sixth-grade children from four private and four public primary schools in Guangzhou in 2014 in a descriptive cross-sectional design. Mental health status was measured by the strengths and difficulties questionnaire. Predisposing characteristics including demographics (e.g., age, gender), social structure (e.g., education, occupation) and health beliefs (health attitude) were recorded. Enabling characteristics including family and community resources and the need for health services were analyzed to explore the risk factors. The results indicate that more rural-to-urban migrant children were classified in the abnormal (21.0%) or borderline (18.8%) categories based on the total difficulties scores, the proportions of which were much higher than those of local children (9.8% abnormal, 13.8% borderline). Factors associated with a greater likelihood of mental health problems included single-parent families, seeking health information actively, family income cannot meet basic needs and poor perceived health status. Compared with the local children, the rural-to-urban migrant children had relatively poor mental health, hence monitoring and supporting mental health for rural-urban migrant children is critical.
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Project description:BackgroundIndia is the second most populated country in the world with 41% of the population (492 million) under 18 years of age. While numerous studies have shown an increasing prevalence of myopia worldwide, there continues to be uncertainty about the magnitude of myopia in Indian school going population.DesignSystematic review and meta-analysis.MethodsWe systematically identified published literature of last four decades from 1980 to March 2020 and assessed them for methodological quality. Data were gathered into 5-year age groups from 5-15, in urban or rural populations, and standardized to definition of myopia as refractive error ≥ -0.50 dioptre. Random effects meta-analysis was done.ResultsWe included data from 59 quality assessed studies, covering nearly 1,66,000 urban and 1,20,000 rural children. The overall crude prevalence of myopia over last four decades is 7.5% (95% CI, 6.5-8.5%) in 5-15-year age group. The prevalence of myopia is 8.5% (95% CI, 7.1-9.9%) in urban and 6.1% (95% CI, 4.5-7.7%) in rural children, with highest prevalence in urban 11-15-year age group [15.0% in last decade]. A significant increment in prevalence is noted in the last decade in rural children from 4.6% to 6.8%, reflecting changing rural environment.ConclusionMyopia is an emerging public health problem in both urban and rural school going adolescents in India requiring urgent efforts.
| S-EPMC7571694 | biostudies-literature
Project description:PURPOSE:To determine the prevalence rate of amblyopia and strabismus in Chinese Hani ethnic school-aged children. METHODS:All grade 1 and grade 7 students in Mojiang Hani Autonomous County, located in southwest China, were invited for comprehensive eye examinations performed by experienced ophthalmologists and optometrists, including visual acuity, ocular alignment and movements, cycloplegic autorefraction, anterior segment and fundus examinations. Standard definitions of amblyopia and strabismus were applied to calculate their prevalence rate. RESULTS:A total of 1656 (91.0% response rate) grade 1 Hani students and 1394 (92.8% response rate) grade 7 Hani students participated in the study. Amblyopia was present in 25 Hani students (0.82%, 95%?CI 0.55% to 1.20%), with no significant differences in grade (p=0.42) and gender (p=0.69). Among these 25 amblyopic children, 17 had unilateral amblyopia and eight had bilateral amblyopia, including 16 anisometropic, eight binocular refractive and one strabismic. Strabismus was found in 59 Hani students (1.93%, 95%?CI 1.50% to 2.48%), including 47 with intermittent exotropia, six with constant exotropia, five with constant esotropia and one with unilateral superior oblique palsy. The prevalence rate of strabismus was higher in grade 7 students than grade 1 students with borderline significance (2.44%vs1.50%, p=0.07), but was similar by gender (2.16% in boys vs 1.68% in girls, p=0.36). CONCLUSION:The prevalence of amblyopia and strabismus in Chinese Hani school children are both lower than that previously reported for Chinese Han children in China and for many other racial/ethnic populations from non-China studies. Refractive error is the major cause for amblyopia and intermittent exotropia is the primary strabismus type.
| S-EPMC6398674 | biostudies-literature
Project description:BackgroundAnxiety disorder is one of the emerging public health problems in many low- and middle-income countries (LMICs). Likewise, in Bangladesh, a growing number of adolescents are experiencing such symptoms though we have very limited research evidence available. The purpose of this study was to investigate the prevalence of anxiety and the factors associated with this condition among urban, semi-urban, and rural school adolescents in Bangladesh.MethodsThis cross-sectional study used a two-stage cluster sampling procedure. A self-administered questionnaire was conveyed to 2355 adolescents from nine secondary schools of Dhaka, Bangladesh. Of the respondents, 2313 completed the seven-item Generalized Anxiety Disorder (GAD-7). Besides, sociodemographic information, self-reported body image as well as modification of Leisure Time Exercise Questionnaire (LTEQ) and WHO Global PA Questionnaire (GPAQ) were used to determine the sociodemographic and lifestyle factors associated with anxiety among adolescents.ResultsA total of 20.1% of adolescents were experiencing moderate to severe anxiety; of them, a significantly higher proportion (49.9%) of female adolescents were suffering more than males (40.1%). Furthermore, age, student's grade, father's educational level, number of family members, and residential setting were found to be significantly associated with anxiety among adolescents. In terms of lifestyle factors, irregular physical activity (AOR: 1.31; 95% CI: 1.05-1.63), high screen time (AOR: 1.51; 95% CI:1.21-1.88), sleep dissatisfaction (AOR: 3.79; 95% CI: 3.02-4.76), and underweight body image (AOR: 2.37; 95% CI:1.70-3.28) were found to be significantly associated with anxiety among school adolescents of urban, semi-urban, and rural residential settings.ConclusionsAnxiety is prevalent among urban, semi-urban, and rural school adolescents in Dhaka, Bangladesh. To lessen this prevalence of anxiety among Bangladeshi adolescents, evidence-based health programs- healthy school trials-and policies should therefore be taken based on the findings of this study.
| S-EPMC8782381 | biostudies-literature
Project description:Myopia, a leading cause of distance vision impairment, is projected to affect half of the world's population in 30 years. We analysed the relationship between certain demographic, environmental, and behavioural factors and myopia from a 2-year school-based, prospective trial conducted in Shanghai, China. This trial enrolled 6295 school-aged children at baseline and followed them up for 24 months. The relationship between abovementioned factors and myopia was examined and the role of sleep in childhood myopia development was highlighted. Our results suggest that 'sleeping late' is a risk factor for myopia prevalence at baseline (odds ratio [OR]?=?1.55, p?=?0.04), 2-year myopia incidence (odds ratio [OR]?=?1.44, p?=?0.02) and progression over 24 months (p?=?0.005), after adjusting for residency area, age, gender, sleep duration, and time spent outdoors. The identification and consistency of results with late sleepers being a susceptible group to both myopia onset and progression suggests a complex relationship between circadian rhythm, indoor environment, habitual indoor activities and myopia development and progression. These results can offer new insights to future myopia aetiology studies as well as aid in decision-making of myopia prevention strategies.
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Project description:Atmospheric particulate matter (PM) is a recognized risk factor for the global burden of disease in human populations. We are presenting here the application of toxicogenomics in the evaluation of the toxic effects of organic content of atmospheric particle matter (PM), from urban and rural environments (city of Barcelona and village of La Pobla, NE Spain), using the developing zebrafish embryo. The main goal is to identify the metabolic pathways involved in the adverse effects observed in zebrafish embryos exposed to PM organic content from urban and rural environments, also allowing the selection of genes of interest that are differentially expressed. The relevance of particle size to the PM toxicity is also addressed. Indeed, the zebrafish embryos were exposed to PM of aerodynamic diameter larger than 7.2 μm and smaller than 0.5 μm (PM10 and PM0.5, respectively). PM0.5 concentrated biological and toxic activities linked to organic substances. Transcriptomic analyses showed strong induction of the AhR signalling pathway (a.k.a. dioxin-like activity) for embryos exposed to both rural and urban extracts, correlating with the concentrations of PAHs. Urban extracts, with strong contribution of traffic emissions, specifically de-regulated oxidative stress-related genes, as well as pancreatic and eye-lens specific genes, two organs known to be affected by air pollution in humans. Exposure to rural extracts, with high contribution of wood burning emissions, affected genes implicated in basic cellular functions, in agreement with their strong embryotoxicity. Extracts from rural and urban samples elicited both common and specific transcriptome responses, suggesting different potentially adverse outcomes depending on PM source and composition. The authors thank the financial support of the Spanish Ministry (project TEA-PARTICLE, grant number CGL2011-29621) and the Portuguese Foundation for Science and Technology for the doctoral grant of Sofia R. Mesquita (SFRH/BD/80710/2011) funded by the Program POPH-QREN through the Portuguese Ministry of Education and Science and the European Social Fund, and support through project PEst-C/MAR/LA0015/2013.
2015-10-26 | GSE53522 | GEO
Project description:BackgroundMyopia is the leading cause of correctable visual impairment and preventable blindness worldwide. Genetic and environmental factors contribute to the development of myopia. Myopia is appearing with greater prevalence in young children.ObjectiveThis study aimed to assess the prevalence and associated factors of myopia among school children in Bahir Dar city, Northwest Ethiopia, 2019.Methods and materialsA school-based cross-sectional study was conducted among school children of 6 to 18 years of age in Bahir Dar city from October to November 2019. A pretested interviewer-administered structured questionnaire was used to collect data among 634 participants using a multi-stage sampling technique from primary and secondary schools. Cycloplegic refraction was performed by optometrists for each student with 1% cyclopentolate eye drop, and subjective refraction was carried out to determine the final prescription of the students. Myopia was defined as spherical equivalent refractive error of ≥ 0.5 diopter in either eye. Data were entered into Epi Info version 7 and exported to Statistical Package for Social Sciences version 23 for analysis. Tables, frequency, and mean were used for descriptive statistics. Bivariable and multivariable logistic regression analyses were done to identify risk factors of myopia. Odds ratio with 95% confidence level was determined and variables with p-value of < 0.05 were considered as statistically significant.ResultsAmong a total of 601 study participants, 51 (8.49%) were myopic. Age group of 10-13 years (AOR = 6.54: 95% CI = 5.56-10.86), 14-18 years (AOR = 6.32: 95% CI = 5.32-9.69), 2-4 hour per day mobile exposure (AOR = 3.69: 95% CI = 1.63-8.38), > 4 hour per day mobile exposure (AOR = 11.6: 95% CI = 4.41-30.42), near working distance of < 33 centimeter (AOR = 6.89: 95% CI = 2.71-17.56) and outdoor activity (AOR = 3.94: 95% CI = 1.87-8.31) were significantly associated with myopia.ConclusionsThe prevalence of myopia was high among school children in Bahir Dar city. Older age, longer duration of mobile exposure, shorter near working distance were the risk factors for the development of myopia whereas having outdoor activity was the protective factor.
| S-EPMC7984635 | biostudies-literature
Project description:BackgroundMyopia is the leading cause of preventable blindness in children and young adults. Multiple epidemiological studies have confirmed a high prevalence of myopia in Asian countries. However, fewer longitudinal studies have been performed to evaluate the secular changes in the prevalence of myopia, especially high myopia in China. In the present study, we investigated trends in the prevalence of myopia among high school students in Fenghua city, eastern China, from 2001 to 2015.MethodsThis was a population-based, retrospective study. Data were collected among 43,858 third-year high school students. Noncycloplegic autorefraction was used to determine refractive error, which was defined as low myopia, moderate myopia, high myopia and very high myopia according to the spherical equivalent from the worse eye of each participant. The prevalence of myopia was calculated and the annual percentage change (APC) was used to quantify the time trends. All analyses were conducted using the SPSS, Stata and Graphpad Prism software.ResultsFrom 2001 to 2015, the prevalence of overall myopia increased from 79.5% to 87.7% (APC =0.59%), with a significant increase of moderate myopia (38.8% to 45.7%, APC?=?0.78%), high myopia (7.9% to 16.6%, APC?=?5.48%) and very high myopia (0.08% to 0.92%, APC?=?14.59%), while the prevalence of low myopia decreased from 32.7% to 24.4% (APC?=?-?1.73%). High myopia and very high myopia contributed the major part of the increasing trend of myopia prevalence (contribution rate 27.00% and 69.07%, respectively).ConclusionsDuring the 15-year period, there was a remarkable increase in the prevalence of high and very high myopia among high school students, which might become a serious public health problem in China for the next few decades.
| S-EPMC6029024 | biostudies-literature
Project description:Atmospheric particulate matter (PM) is a recognized risk factor for the global burden of disease in human populations. We are presenting here the application of toxicogenomics in the evaluation of the toxic effects of organic content of atmospheric particle matter (PM), from urban and rural environments (city of Barcelona and village of La Pobla, NE Spain), using the developing zebrafish embryo. The main goal is to identify the metabolic pathways involved in the adverse effects observed in zebrafish embryos exposed to PM organic content from urban and rural environments, also allowing the selection of genes of interest that are differentially expressed. The relevance of particle size to the PM toxicity is also addressed. Indeed, the zebrafish embryos were exposed to PM of aerodynamic diameter larger than 7.2 μm and smaller than 0.5 μm (PM10 and PM0.5, respectively). PM0.5 concentrated biological and toxic activities linked to organic substances. Transcriptomic analyses showed strong induction of the AhR signalling pathway (a.k.a. dioxin-like activity) for embryos exposed to both rural and urban extracts, correlating with the concentrations of PAHs. Urban extracts, with strong contribution of traffic emissions, specifically de-regulated oxidative stress-related genes, as well as pancreatic and eye-lens specific genes, two organs known to be affected by air pollution in humans. Exposure to rural extracts, with high contribution of wood burning emissions, affected genes implicated in basic cellular functions, in agreement with their strong embryotoxicity. Extracts from rural and urban samples elicited both common and specific transcriptome responses, suggesting different potentially adverse outcomes depending on PM source and composition. The authors thank the financial support of the Spanish Ministry (project TEA-PARTICLE, grant number CGL2011-29621) and the Portuguese Foundation for Science and Technology for the doctoral grant of Sofia R. Mesquita (SFRH/BD/80710/2011) funded by the Program POPH-QREN through the Portuguese Ministry of Education and Science and the European Social Fund, and support through project PEst-C/MAR/LA0015/2013. The PM filter samples used in the present study were PM10 and PM0.5 from the urban site - total of 4 samples from 2 sampling months; and PM0.5 from the rural site - total of 2 samples from 2 sampling months (PM10 samples from the rural site were not tested due to their very low concentration in organic compounds, and insignificant biological activity, previously measured). Sampling occurred during the cold periods of the year 2012/2013. The organic fraction of PM samples was extracted by sonication using a mixture of dichloromethane:methanol. Then, the extracts were filtered, evaporated and re-dissolved in Dimethyl sulfoxide (DMSO). Zebrafish fertilized eggs were exposed to PM organic extracts (0.2% DMSO) from the urban and rural sites from 24 to 120h post-fertilization. Total RNA was isolated from whole embryos (pools of 20 individuals), using Trizol reagent protocol (Invitrogen Life Technologies, Carlsberg, CA). The microarray study was performed using the Agilent Two-colour D. rerio Oligo Microarray v3 platform, following the Agilent Microarray â?? Based Gene Expression Analysis protocol. Three biological replicates were performed for each PM sample and controls. Biological replicates, a technical replicate and a self-to-self, were simultaneously amplified and labelled using Cyanine 3 (Cy3) and Cyanine 5 (Cy5) dye. After cRNA purification (RNeasy Kit, Quiagen GmbH, Hilden, Germany), the cRNA concentration and labelling were quantified in the NanoDrop spectrophotometer, obtaining incorporation rates in the range of 15-20pmol of cyanide dye/µl cRNA and yield values > 0.825ug, as recommended. cRNA was fragmented and hybridized in 4x44K arrays, for 17h at 65oC. After the hybridization the array slides were washed, and immediately scanned using Microarray Scanner Agilent G2505C system. Data was extracted using Agilent Feature Extraction Software v10.5.1.1, and the quality of microarray data was evaluated using the Quality Control report provided by Agilent Software. Based on the microarray data analysis, 22 primers were selected and designed using Primer Express 2.0 software (Applied Biosystems, Foster City, CA). Genes were quantified by real-time PCR to validate the microarray data, and a subset of 13 genes were further selected by their robust behaviour in the validation assays, allowing to differentiate the toxic potential of PM from urban and rural sources.
2015-10-26 | E-GEOD-53522 | biostudies-arrayexpress