Breastfeeding and myopia: A cross-sectional study of children aged 6-12 years in Tianjin, China

Association between body stature and prevalence of reduced visual acuity in high school graduates in Hangzhou, China

CLINICAL RELEVANCE

The association between myopia and body stature is of great significance for understanding prevention and control of myopia. It has been extensively studied in previous studies but without consistent conclusions.

BACKGROUND

The aim of this study is to investigate the association between body stature and prevalence of reduced visual acuity in high school graduates in Hangzhou, China.

METHODS

50,620 high school graduates who finished the physical examination of the national college entrance examination in 2020 were included. Data were derived from the database of physical examination of the national college entrance examination. Height and weight were measured, and body mass index (BMI) was calculated according to the general formula. Visual acuity was measured by the standard logarithmic visual acuity chart.

RESULTS

The prevalence of reduced visual acuity was 90.38% in high school graduates. Girls had a higher prevalence of reduced visual acuity than boys (93.07% vs 87.60%, P < 0.001). Boys with normal visual acuity were significantly taller (P < 0.001) and heavier (P < 0.001) than those with reduced visual acuity. Girls with normal visual acuity were significantly taller than those with reduced visual acuity (P < 0.001). The prevalence of reduced visual acuity was significantly inversely associated with height in both boys (P < 0.001) and girls (P < 0.001). The risk of reduced visual acuity was the lowest in the fourth quartile of height. The prevalence of reduced visual acuity was significantly associated with BMI only in boys (P < 0.001). The risk of reduced visual acuity was the lowest in the third quartile of BMI.

CONCLUSIONS

The prevalence of reduced visual acuity was inversely associated with height in both boys and girls, and there was a U-shaped association with BMI only in boys.

The Myopia Prevalence and Association With Physical Activity Among Primary School Students Aged 6-12 Years: A Cross-Sectional Study in Tianjin, China

Purpose

This study aimed to investigate the prevalence of myopia and determine the association between physical activity and risk of myopia among primary school students in Tianjin, China.

Methods

A cross-sectional study was conducted among subjects from nine primary schools. All of the subjects underwent visual acuity and spherical equivalent (SE) with noncycloplegic autorefraction measurement. Myopia was defined as an SE refraction ≤-0.50D and an uncorrected visual acuity <5.0 in either eye. Physical activity was measured via the Physical Activity Questionnaire for Children. Data were analyzed using the Pearson χ2 test and binary logistic regression. Stratification analysis by sex was also performed.

Results

A total of 2976 participants (1408 boys and 1568 girls) aged six to 12 years (mean age 8.82 years) were included in this study. The overall prevalence of myopia was 52.92%. When stratified according to physical activity, myopia prevalence significantly decreased with increasing physical activity levels (χ2 trend test = 127.63, P < 0.001). In the binary logistic regression analysis, after adjusting for age, sex, and school region, the odds ratio for the association between physical activity and myopia was 0.762 (95% confidence interval, 0.675-0.862, P < 0.001). When stratified by sex, the significant statistical association between physical activity and myopia both can be found in two groups (P < 0.05).

Conclusions

Higher levels of physical activity were independently associated with decreased risk of myopia. The significant reverse statistical association between physical activity and myopia can be found in male or female groups.

Translational Relevance

Taking part in physical activities may be an effective way to reduce the prevalence of myopia.

Innovative Food Safety Approaches and Nutraceuticals to Promote Children's Health on Future Outbreaks with the Reflection of COVID-19

After the COVID-19 pandemic, innovative methods have emerged for the management of food safety, child nutrition has become more important than ever, and increasing attention has been paid to the consequences of COVID-19. For instance, since SARS-CoV-2 is an animal-based zoonotic virus, there is a changing trend in consumer preferences from conventional meat products to cultured meat and vegan supplementation. Due to the effects mentioned, this chapter provides strategic guidance on novel foods, food safety innovations, and novel health and safety procedures in public places such as restaurants or bars. There are also long-term health impacts on children in the aftermath of COVID-19. Since the risk of myopia is one of the important long-term effects to be considered, trending nutritional immunology approaches are presented to reduce emerging problems in child eye health. The enhancement of immune system remains problematic for many children considering that they cannot use the COVID-19 vaccine. Therefore, this chapter also emphasizes the importance of breastfeeding on the side effects of viral infections and new supplements, such as probiotic drops, to improve children's and babies' immune health. Additionally, efforts should be undertaken to improve nanoencapsulation techniques to prepare for future epidemics and pandemics. Nanomaterial-supported nutraceuticals, nanoencapsulation of functional ingredients or their nanoparticles, and nano-combination of phytochemicals, fatty acids, or probiotics should be investigated to improve the immunity of children. In this sense, detailed further research in this area needs to be adapted to innovative technologies for the treatment of infants and children against future zoonotic viruses.

The Role of Cow's Milk Consumption in Breast Cancer Initiation and Progression

PURPOSE OF REVIEW

This review evaluates cow milk's impact on breast carcinogenesis by linking recent epidemiological evidence and new insights into the molecular signaling of milk and its constituents in breast cancer (BCa) pathogenesis.

RECENT FINDINGS

Recent prospective cohort studies support the association between cow's milk consumption and the risk of estrogen receptor-α-positive (ER⁺) BCa. Milk is a complex biological fluid that increases systemic insulin-like growth factor 1 (IGF-1), insulin and estrogen signaling, and interacting hormonal promoters of BCa. Further potential oncogenic components of commercial milk include exosomal microRNAs (miR-148a-3p, miR-21-5p), bovine meat and milk factors, aflatoxin M1, bisphenol A, pesticides, and micro- and nanoplastics. Individuals with BRCA1 loss-of-function mutations and FTO and IGF1 gain-of-function polymorphisms enhancing IGF-1/mTORC1 signaling may be at increased risk for milk-induced ER⁺ BCa. Recent prospective epidemiological and pathobiochemical studies identify commercial milk consumption as a critical risk factor of ER⁺ BCa. Large meta-analyses gathering individuals of different ethnic origins with milk derived from dairy cows of varying genetic backgrounds and diverse feeding procedures as well as missing data on thermal processing of milk (pasteurization versus ultra-heat treatment) make multi-national meta-analyses unsuitable for BCa risk estimations in susceptible populations. Future studies are required that consider all vulnerable periods of breast carcinogenesis to cow's milk exposure, beginning during the perinatal period and puberty, since these are the most critical periods of mammary gland morphogenesis. Notwithstanding the need for better studies including detailed information on milk processing and vulnerable periods of human breast carcinogenesis, the available evidence suggests that dietary guidelines on milk consumption may have to be reconsidered.

Breastfeeding in Neonates Admitted to an NICU: 18-Month Follow-Up

Introduction: The admission of neonates to Neonatal Intensive Care Units (NICUs) has been identified as a primary inhibiting factor in the establishment of breastfeeding. The aims of this study were to (1) estimate the prevalence and duration of breastfeeding in infants/toddlers who had been admitted to an NICU in Greece and (2) to investigate factors, associated with the NICU stay, which affected the establishment and maintenance of breastfeeding in infants/toddlers previously admitted to the NICU. Materials and methods: Data for this cohort study were retrieved from interviews with mothers of infants/toddlers who had been admitted to our NICU as neonates during the period of 2017−2019. Interviews were conducted based on a questionnaire regarding the child’s nutrition from birth to the day of the interview, including previous maternal experience with breastfeeding. Information related to the prenatal period, gestation age, delivery mode, duration of NICU stay, and neonatal feeding strategies during their hospital stay were recorded. Results: The response rate to the telephone interviews was 57%, resulting in 279 mother−infant pairs being included in this study. The results showed that 78.1% of children received maternal milk during their first days of life. Of all infants, 58.1% were exclusively breastfed during their first month, with a gradual decrease to 36.9% and 19.4% by the end of the third and sixth months of life, respectively. The prevalence of breastfed children reached 14.7% and 7.5% at the ages of twelve and eighteen months, respectively. In the multivariate analysis, prematurity emerged as an independent prognostic factor for the duration of exclusive and any breastfeeding (aHR 1.64, 95% CI: 1.03−2.62; and 1.69, 95% CI: 1.05−2.72, respectively; p < 0.05). Additionally, the nationality of the mother, NICU breastfeeding experience, the administration of maternal milk during neonatal hospital stay, and previous breastfeeding experience of the mother were independent prognostic factors for the duration of breastfeeding. Conclusions: Although breastfeeding is a top priority in our NICU, the exclusive-breastfeeding rates at 6 months were quite low for the hospitalized neonates, not reaching World Health Organization (WHO) recommendations. Mothers/families of hospitalized neonates should receive integrated psychological and practical breastfeeding support and guidance.

The Association Between Refractive Errors and Breastfeeding in Pakistani Children: A Case-Control Study

Objective

The aim of this study was to determine the association between breastfeeding and the occurrence of refractive errors (REs) among children.

Methodology

This was a (retrospective) case-control study carried out between December 1, 2021, and March 30, 2022, at the Basheeran Umar Eye Hospital in Islamabad, Pakistan, and Sheikh Khalifa bin Zayed Al Nayhan Combined Military Hospital in Rawalakot in Kashmir, Pakistan. A total of 200 participants between the ages of five and 16 years (106 cases with REs and 94 controls without REs) were included in this study. After obtaining informed consent from the parent accompanying the participant, the parent was further interviewed to extract information regarding biodata, breastfeeding, and other parameters including parental myopia, the number of hours spent on outdoor activities, on gadgets, and doing near work; this data was entered into a questionnaire. The participant’s visual acuity was then checked using the Snellen chart. Data were analyzed using SPSS Statistics version 20.0 (IBM Corp., Armonk, NY) and statistical tests such as multivariate regression analysis and chi-square were carried out and odds ratios (OR) were calculated.

Results

There were 74 (37%) females and 126 (63%) males, with 67.5% residing in urban localities and only 32.5% hailing from rural areas. Testing revealed no significant association between REs and area of residence (p=0.97) or the gender of the participant (p=0.74). Hypermetropia was the most common RE among our participants (59.4%).

Breastfeeding was significantly associated with errors of refraction (OR: 27.852, 95% CI: 3.686-210.45, χ²=21.680, p<0.001, degrees of freedom: 1), and we observed a lower risk of REs in children who had been breastfed. There was no association between REs and the number of hours spent outdoors per week or the number of hours spent using gadgets per week. However, there was a significant association between the development of REs and the duration of breastfeeding and the number of hours spent on near work.

Conclusion

This study demonstrates that breastfeeding plays a protective role in the prevention of REs. The type of breastfeeding also had a significant effect on the development of REs, i.e., children exclusively breastfed (regardless of the duration of breastfeeding) were less likely to develop errors of refraction in the future.

The Prevalence and Progression of Myopia in Elementary School Students in Shanxi Province, China During the COVID-19 Pandemic

PURPOSE

To investigate the prevalence of myopia and the risk factors associated with its progression in elementary school students during the COVID-19 pandemic in Shanxi Province, China.

METHODS

The investigation included 960 students spanning first to sixth grade from six elementary schools in Shanxi Province, China. All participants received non-cycloplegic refraction and vision tests in December of 2019 (before the COVID-19 pandemic) and in June of 2020 (after classes resumed). Information concerning the students' eye-use behaviors, physical activities, diet and sleep during the pandemic was collected using a questionnaire survey. A total of 913 students (457 males) completed all tests and the questionnaire.

RESULTS

The overall prevalence rate of myopia was 16.6% in December of 2019, and it increased with age. There was no gender difference in the prevalence of myopia (χ² = 3.210, P = .073), but females exhibited a lower average spherical equivalent (SE) (P = .026). When the classes were resumed 6 months later, the overall prevalence rate of myopia was found to be 39.4%, which was significantly higher than it before the pandemic (χ² = 117.425, P < .001). The average SE of the participants was -0.95D, which was significantly lower than the average SE (-0.43D) before the pandemic (P < .001). SE variation (ΔSE) in grade 6 was significantly higher than that in grade 1. No significant difference in ΔSE was found between males and females. Analyses of ordinary least squares (OLS)-estimated linear, natural logarithmic and quadratic functions revealed that the progression of myopia during the COVID-19 pandemic was significantly correlated with screen time, types of electronic devices, the amount of sleep, age, and the number of parents with myopia.

CONCLUSIONS

The prevalence rate and progression of myopia among elementary school students in Shanxi Province increased significantly during the COVID-19 pandemic, which was likely related to China's home-based online learning programs. Therefore, it is necessary to optimize the educational programs for elementary school students when they study at home. We recommend increased time for outdoor activities and limiting screen time.

Refractive errors and visual impairment among children and adolescents in southernmost China

Background

Refractive errors and visual impairment in southernmost China have not been reported previously. We aim to investigate and determine the age-specific prevalence of myopia, hyperopia, astigmatism, and visual impairment based on a large population cross-sectional study in Hainan area of southernmost tropical province in China.

Methods

A population-based sample of 31,524 children aged 615years from Hainan was assessed. Non-cycloplegic autorefraction and visual acuity (VA) analyses were performed on all participants and a subgroup of participants undergoing cycloplegia.

Results

Of all participants, 23.0% presented uncorrected VA (UCVA) was worse than 20/40 in worse eye, 6.0% presented mild presenting visual acuity impairment (PVAI), 7.0% presented moderate PVAI, 0.2% presented severe PVAI in the better eye, and 46.9% presented abnormal UCVA [worse than 20/25 (6,<8years old) and worse than 20/20 (8years and older)] at least in one eye. The overall prevalence of myopia [spherical equivalent (SE)0.50 D] and high myopia (SE6.00 D) were 46.0%, 1.0% respectively. Hyperopia [SE+1.00 D (7years old) and SE+2.00 D (6,<7years old)] and significant hyperopia (SE+3.00 D) were 4.2 and 0.6%, respectively. Astigmatism [cylinder1.00 D (7years old) and1.75 D (6,<7years old)] was found in 31.9%.

Conclusions

Myopia was the most common refractive error in southernmost province in China (Hainan). Its prevalence increased with age, while hyperopia prevalence showed a decreasing trend. However, myopia, especially high myopia prevalence was much lower than in other urban regions across China.

Recent Epidemiology Study Data of Myopia

Myopia, a pandemic refractive error, is affecting more and more people. The progression of myopia could cause numerously serious complications, even leading to blindness. This review summarizes the epidemiological studies on myopia after 2018 and analyzes the risk factors associated with myopia. The prevalence of myopia varies in different regions, age, and observation time. East Asia has been gripped by an unprecedented rise in myopia, and other parts of the world have also seen an increase. The prevalence of myopia in children continues to rise and aggravates with age. The prevalence of high myopia has also increased along with myopia. Racial dependence and family aggregation can be seen frequently in myopia patients. Increased outdoor activities are proven to be protective factors for myopia, as near-distance work and higher education levels affect in the opposite. The impact of gender or urbanization on myopia is controversial. The relationship between nutrition, digital screens, Kawasaki disease, pregnant women smoking during pregnancy, and myopia is still not clear for lack of sufficient evidence. Understanding the various factors that affect myopia helps to clarify the mechanism of myopia formation and also to formulate reasonable prevention and control measures of myopia to protect people's health, especially for adolescents.

Prenatal and neonatal factors for the development of childhood visual impairment in primary and middle school students: a cross-sectional survey in Guangzhou, China

OBJECTIVES

In this cross-sectional survey, we sought to determine the prevalence of and the influence of prenatal and neonatal factors on childhood visual impairment without correction (VIUC) in a paediatric population from Guangzhou, China.

SETTING

The health survey covered 11 administrative districts in Guangzhou, including 991 schools.

PARTICIPANTS

All of the primary and middle school students in Guangzhou were invited to complete an online questionnaire with the help of their parents. The results of physical examinations were reported by school medical departments. The results of the questionnaire were collected by the researchers. In total, 253 301 questionnaires were collected.

PRIMARY OUTCOME MEASURES

The students' uncorrected visual acuity (UCVA) was examined by trained optometrists by standard logarithmic visual acuity charts. VIUC was defined by UCVA (of the better eye) (UCVA <6/12) with three levels: light VIUC (UCVA ≥6/18 to <6/12), mild VIUC (UCVA ≥6/60 to <6/18) and severe VIUC (UCVA <6/60).

RESULTS

A total of 39 768 individuals (15.7%) had VIUC, and the rate was much higher among grade 10 to 12 students (51.4%) than among grade 1 to 6 students (6.71%). The following factors were significantly associated with an increased risk of VIUC: female gender, high birth weight, formula feeding, not having siblings, higher level of parents' education, parental myopia, much homework time and little outdoor activity. Delivery mode was not associated with the risk of VIUC.

CONCLUSIONS

This study validates known major prenatal/genetic, perinatal and postnatal factors for childhood VIUC. In conclusion, prenatal and perinatal factors can affect the onset of childhood VIUC, but parental myopia and postnatal factors are the main factors.

Prevalence of myopia and associated risk factors among primary students in Chongqing: multilevel modeling

Background

The prevalence of myopia and associated risk factors among children in Chongqing has not yet been determined. This study investigated the prevalence of myopia and possible relationships between myopia and several related factors among school children in Chongqing.

Methods

This cross-sectional study assessed a sample of 997 children (7–13 years of age) attending primary school in Chongqing. Data were obtained from visual acuity and refractive error measurements and a structured questionnaire. Myopia was defined as visual acuity < 5.0 and refractive error (spherical equivalent) of < − 0.50 diopters (D) in either eye. Multilevel modeling was applied to investigate potential risk factors.

Results

The overall prevalence of myopia was 33.9% [95% confidence interval (CI) = 31.0–36.8]; myopia prevalence significantly increased with age. Girls were at a higher risk of myopia than boys [odds ratio (OR) = 1.449, 95% CI = 1.060–1.979]. Children with paternal myopia (OR = 2.130, 95% CI = 1.376–3.297) or maternal myopia (OR = 1.861, 95% CI =1.153–3.002) had a higher risk of myopia than those without myopic parents. Children who spent more than 1 h daily outdoors were less likely to have myopia; meanwhile, children who did homework more than 3 h daily (OR = 2.237, 95% CI = 1.041–4.804), watched television more than 3 h daily (OR = 2.106, 95% CI = 1.200–3.697), or played electronics more than 1 h daily (OR = 2.983, 95% CI = 2.088–4.262) had a higher risk of myopia.

Conclusions

Myopia in school children is a serious public health problem in Chongqing. Myopia was significantly positively associated with higher age, female sex, parental myopia, and spending a long time indoors; notably, playing with electronics had the greatest influence on the risk of myopia.

The Lack of Association of Breastfeeding and Myopia in Children and Adolescents: Finding from a School-Based Study and a Meta-Analysis of the Literature

Background: We aimed to assess the relationship between breastfeeding and myopia in a school-based study in rural China. In addition, we performed a systematic review and meta-analysis to confirm the association from available observational studies. Materials and Methods: The school-based study of 2,346 grade 7 students (mean age: 13.8 years) was conducted in southwestern part of China. Myopia was defined as spherical equivalent of less than -0.50 diopter and information regarding breastfeeding was ascertained through a questionnaire. We also performed the literature search in three databases (PubMed, EMBASE, and Cochrane Central Register of Controlled Trials) and reference lists of retrieved studies. Effect estimates were pooled using random-effects models. Results: In our school-based study, the association between breastfeeding and myopia was marginally nonsignificant after adjusting for potential confounders, including gender, body mass index, parental myopia, time for reading and writing after school, and time outdoors (odds ratio = 0.75, 95% confidence interval: 0.55-1.04, p = 0.09). In the meta-analysis of eight studies, no significant association was observed. Conclusion: Current evidence did not support that breastfeeding could reduce the risk of myopia in children and adolescents.

Comparative Effect of Feeding Human Milk as Opposed to Formula on Visual Function and Ocular Anatomy

Background/Objective: Performance of ocular examinations on children who were breastfed, fed with formula, and combination of the two for the first 6 months of age. Subsequently, refractive errors, allergic conjunctivitis, and retinal nerve fiber layer (RNFL) thickness were evaluated. Materials and Methods: The present study included a total of 242 eyes of 121 children (aged 60-84 months, 65 males, 56 females) admitted to the outpatient clinic of our institution. The patients were divided into three groups according to their feeding pattern during their first 6 months postdelivery: breastfed children (Group 1, n = 40), children fed with a combination of breast and formula milk (Group 2, n = 41), and children exclusively fed with formula-milk (Group 3, n = 40). All patients underwent detailed ophthalmologic examinations, and measurements of the RNFLs were recorded. Results: No significant difference was observed between the groups in terms of refractive error. In Group 3, we found that allergic conjunctivitis was significantly higher than in the other groups. In addition, in Group 3, the thickness of the RNFL was found to be significantly higher in the superior quadrants of both the eyes of children than in Groups 1 and 2 (p < 0.05). Conclusions: We found that the type of feeding experienced by infants in their first 6 months has no effect on refractive error but has significant effects on both allergic conjunctivitis and RNFL. To determine the cause of this difference in the RNFL and to further validate the present study, future studies with larger patient groups and animal experiments are needed.