Body mass index and astigmatism: A nationwide study.

BACKGROUND: Existing research on the relationship between body mass index (BMI) and astigmatism yields inconsistent results. This study analyses this association in a nationally representative sample of adolescents. METHODS: This retrospective, cross-sectional study included Israeli adolescents who underwent medical assessments before mandatory military service between 2011 and 2022. BMI was categorised based on the US age- and sex-matched percentiles. Astigmatism was categorised by magnitude [low-moderate: 0.75 to <3.00 diopters (D), high: ≥3.00 D], and axis orientation [with-the-rule (WTR), against-the-rule (ATR), or oblique (OBL)]. Sex-stratified regression models adjusted for sociodemographic variables were used. RESULTS: Of 935 989 adolescents evaluated, 887 325 were included [511 465 (57.6%) males, mean age 17.2 years]. Astigmatism was diagnosed in 123 675 (13.9%) adolescents, of whom 117 081 (13.2%) had low-moderate and 6594 (0.7%) had high astigmatism. WTR astigmatism was the most prevalent (8.2%), followed by ATR (4.1%) and OBL (1.6%) types. Compared with low-normal BMI (5th to 50th percentile), the adjusted ORs for total astigmatism increased with increasing BMI, peaking at 1.65 (1.57-1.74) in males and 1.74 (1.64-1.86) in females with severe obesity. ORs were accentuated for high astigmatism, reaching 3.51 (3.01-4.09) in males, and 3.45 (2.83-4.22) in females with severe obesity. WTR astigmatism demonstrated the strongest association with BMI, with ORs reaching 2.26 (2.13-2.40) in males and 2.04 (1.90-2.20) in females with severe obesity. The results persisted in a series of subgroup analyses. CONCLUSIONS: Obesity is associated with higher odds of astigmatism in adolescence. Further investigation into the role of weight management in astigmatism development is warranted.

Acceptance of Seasonal Influenza Vaccine Following COVID-19 Vaccination: A Survey among Israel Defense Forces Soldiers.

Data regarding the contribution of COVID-19 vaccine rollouts to real-world uptake of influenza vaccination remains unclear. This cross-sectional survey-based study among Israel Defense Forces (IDF) soldiers aimed to assess the impact of the COVID-19 pandemic and specifically, previous COVID-19 vaccines uptake, on the intention to vaccinate for influenza during 2021-2022 season. Participants engaged in an online survey addressing vaccination history and current vaccine-related preferences. The survey was delivered prior to the initiation of the IDF's annual influenza immunization campaign. A multinomial logistic regression model was applied to analyze factors correlated with unwillingness to receive influenza vaccine. Overall, 825 invitations to participate in the survey were distributed and the overall response rate was 78.5%. Among the 648 participants who replied (61.6% males, median age of 20 years), 51.9% were willing to receive the upcoming influenza vaccine. Factors associated with vaccine reluctance included being female, not receiving the previous season's influenza vaccine, not having a previous diagnosis of COVID-19, and having decreased uptake of COVID-19 vaccines. Among participants not intending to receive an influenza vaccine, 50.3% stated that they are healthy and have no need for the vaccine and 36.2% stated they received too many vaccines over the previous year. The results of this study may suggest that influenza vaccination rates in the post-COVID-19 vaccine era may be reduced due to a perceived "vaccine saturation" phenomenon, owing to the density of COVID-19 vaccine administration. Future interventions such as campaigns related to maximizing influenza vaccination coverage should address repeated doses of COVID-19 vaccine administration.

The Significance of Body Surface Area to Mass Ratio for Thermal Responses to a Standardized Exercise-Heat Stress Test.

PURPOSE: To evaluate the significance of body surface area-to-mass ratio (BSA/mass) on the heat-tolerance test (HTT) results. We hypothesized that individuals defined as heat tolerant (HT) would have on average higher BSA/mass compared to heat intolerant (HI) individuals. METHODS: A retrospective reanalysis of the HTT results of 517 soldiers (age: 18-38 yrs., M/F: 96/4%), who were tested by the Israel Defense Forces (IDF) HTT protocol. The criterion for heat tolerance in the current analysis was a rectal temperature (Tre) plateau during the second hour of the test. A logistic regression analysis to evaluate the predictive power of BSA/mass for heat intolerance was performed; the spline model was applied to show the odds for heat intolerance across BSA/mass. RESULTS: In men BSA/mass of HI individuals was lower than HT individuals (248 ± 19 vs. 262 ± 18 cm2/kg, p < 0.01, d = 0.76). In women a similar trend was noted but with no statistical significance between HT and HI groups. The odd ratio for heat intolerance for every unit increase in BSA/mass was 0.97 (CI 95% 0.95-0.99). The spline model plateaued above BSA/mass of 270 cm2/kg. CONCLUSIONS: The results imply that body-core temperature responses to a standard exercise-heat stress (fixed external work rate and climatic conditions) are influenced by BSA/mass. More specifically, lack of a steady state in Tre (indicating heat intolerance) was more likely to occur with every unit decrease in BSA/mass. These findings contribute to a better understanding of the role of body anthropometry in the response to a standard exercise-heat task that might have an implication on clinical decision-making about return to duty/play of soldiers, athletes and others who deemed to be identified as HI.

Body mass index and visual impairment in Israeli adolescents: A nationwide study.

BACKGROUND: Previous research on the association between body mass index (BMI) and visual impairment (VI) in youth has reported inconsistent findings. We aimed to investigate this association in a national cohort of Israeli adolescents. METHODS: This retrospective, population-based, cross-sectional study included 1 697 060 adolescents (56.4% men; mean age 17 years) who underwent mandatory pre-military service assessments from 1993 to 2017. BMI was classified based on the US age- and sex-matched percentiles. Unilateral or bilateral VI was classified as best-corrected visual acuity (BCVA) worse than 6/9 in either or both eyes, respectively. Sex-stratified regression models adjusted for sociodemographic variables were used to analyse the BMI-VI relationship. RESULTS: Overall, 17 871 (1.05%) and 5148 (0.30%) adolescents had unilateral and bilateral VI, respectively. Compared with high-normal BMI (50th to 85th percentile), adjusted odds ratios (ORs) for unilateral and bilateral VI gradually increased with higher BMI, reaching 1.33 (1.13-1.55) and 1.80 (1.37-2.35) in men with severe obesity, and 1.51 (1.24-1.84) and 1.52 (1.08-2.14) in women with severe obesity, respectively. Men with underweight also had increased ORs for unilateral and bilateral VI (1.23; 1.14-1.33 and 1.59; 1.37-1.84, respectively), a pattern not observed in women (0.96; 0.86-1.07 and 1.02; 0.83-1.25, respectively). Results were maintained when the outcome was restricted to mild VI, as well as in subgroups of adolescents with unimpaired health and those without moderate-to-severe myopia. CONCLUSIONS: Abnormal BMI, and particularly obesity, is associated with increased OR for VI in late adolescence.

Long-Term Disability After Traumatic Spinal Injuries: A Military Retrospective Study.

BACKGROUND: Traumatic spinal injuries (TSI) pose a significant life-long burden, impacting both military and civilian populations. Assessing long-term outcomes is crucial for comprehending the enduring consequences of the initial insult and informing effective prevention and management strategies. Most existing studies have narrowly focused on subsets of traumatic cord injuries, leaving a gap in understanding the broader impact of severe spinal trauma. This study aims to examine severe TSIs in military personnel, who may face unique risk factors and injury patterns, and its association with long-term disability. METHODS: A retrospective cohort study was conducted on all military personnel who suffered traumatic injuries (Injury Severity Score ≥ 9) from 1997 to 2020. Severe spinal injuries were defined using the spinal Abbreviated Injury Scale ≥ 3 (n = 95), and compared to all other injuries as a reference group (n = 1,394). Data were extracted and cross-referenced from three distinct nationwide registries-pre-hospital, admission, and rehabilitation. Logistic regression analysis was used to evaluate the impact of spinal injuries on long-term disabilities (defined as the highest possible disability tier). The study received approval from the institutional review board of the Israel Defense Forces Medical Corps. RESULTS: Motor vehicle accidents and falls were the primary causes of spinal injuries (50.5% and 15.8%, respectively). The median age at injury was 20 years (interquartile range 19-22). Personnel with spinal trauma had a significantly higher prevalence of Injury Severity Score ≥ 25 (46.3% vs. 19.9%, P < .001), longer median hospital stays (11 vs. 8 days, P = .036), and increased intensive care unit admissions (55% vs. 40%, P = .05). The median follow-up duration was 10.9 years (interquartile range 6.7-14.3). Spinal injuries were associated with a more than 10-fold increase in the adjusted odds ratio for severe permanent disability (11.92, 95% CI, 5.95-23.72). CONCLUSION: Upon long-term follow-up, military personnel with severe TSI exhibit a significantly higher prevalence of debilitating disability compared to those with significant non-spinal traumatic injuries. These findings highlight the critical need for targeted prevention strategies and improved management of spinal injuries to reduce long-term disability. Strengths of this study include its extensive follow-up period and the use of multiple nationwide registries. However, the study may be limited by potential discrepancies in identity matching across databases and the reliance on disability claims, which may underrepresent the true prevalence of long-term disability. Future research should explore the efficacy of early interventions and rehabilitation strategies in mitigating long-term disability following spinal injuries. This study underscores the importance of developing evidence-based policies to enhance care for individuals with TSIs.

Adolescent Body Mass Index and Early Chronic Kidney Disease in Young Adulthood.

Importance: Despite increasing obesity rates in adolescents, data regarding early kidney sequelae are lacking. Objective: To assess the association between adolescent body mass index (BMI) and early chronic kidney disease (CKD) in young adulthood (<45 years of age). Design, Setting, and Participants: This cohort study linked screening data of mandatory medical assessments of Israeli adolescents to data from a CKD registry of a national health care system. Adolescents who were aged 16 to 20 years; born since January 1, 1975; medically evaluated for mandatory military service through December 31, 2019; and insured by Maccabi Healthcare Services were assessed. Individuals with kidney pathology, albuminuria, hypertension, dysglycemia, or missing blood pressure or BMI data were excluded. Body mass index was calculated as weight in kilograms divided by height in meters squared and categorized by age- and sex-matched percentiles according to the US Centers for Disease Control and Prevention. Follow-up started at the time of medical evaluation or January 1, 2000 (whichever came last), and ended at early CKD onset, death, the last day insured, or August 23, 2020 (whichever came first). Data analysis was performed from December 19, 2021, to September 11, 2023. Main Outcomes and Measures: Early CKD, defined as stage 1 to 2 CKD by moderately or severely increased albuminuria, with an estimated glomerular filtration rate of 60 mL/min/1.73 m2 or higher. Results: Of 629 168 adolescents evaluated, 593 660 (mean [SD] age at study entry, 17.2 [0.5] years; 323 293 [54.5%] male, 270 367 [45.5%] female) were included in the analysis. During a mean (SD) follow-up of 13.4 (5.5) years for males and 13.4 (5.6) years for females, 1963 adolescents (0.3%) developed early CKD. Among males, the adjusted hazard ratios were 1.8 (95% CI, 1.5-2.2) for adolescents with high-normal BMI, 4.0 (95% CI, 3.3-5.0) for those with overweight, 6.7 (95% CI, 5.4-8.4) for those with mild obesity, and 9.4 (95% CI, 6.6-13.5) for those with severe obesity. Among females, the hazard ratios were 1.4 (95% CI, 1.2-1.6) for those with high-normal BMI, 2.3 (95% CI, 1.9-2.8) for those with overweight, 2.7 (95% CI, 2.1-3.6) for those with mild obesity, and 4.3 (95% CI, 2.8-6.5) for those with severe obesity. The results were similar when the cohort was limited to individuals who were seemingly healthy as adolescents, individuals surveyed up to 30 years of age, or those free of diabetes and hypertension at the end of the follow-up. Conclusions and Relevance: In this cohort study, high BMI in late adolescence was associated with early CKD in young adulthood. The risk was also present in seemingly healthy individuals with high-normal BMI and before 30 years of age, and a greater risk was seen among those with severe obesity. These findings underscore the importance of mitigating adolescent obesity rates and managing risk factors for kidney disease in adolescents with high BMI.

The Definition-Dependent Nature of Myopia Prevalence: A Nationwide Study of 1.5 Million Adolescents.

PURPOSE: The application of myopia definition varies considerably within the literature. The purpose of this study was to examine the relationship between different myopia and high myopia definitions and resultant prevalence estimates. METHODS: A population-based cross-sectional study of 1,588,508 Israeli adolescents assessed for medical fitness before mandatory military service at the age of 17 years between 1993 through 2015. Participants underwent non-cycloplegic autorefraction. Nine definitions of myopia and seven definitions of high myopia were examined. Prevalence estimates for each definition were calculated and compared with the reference definition (right eye spherical equivalent (SE)≤-0.50D and ≤-6.00D for myopia and high myopia, respectively), to yield a rate ratio (RR) across definitions. RESULTS: Applying the right eye SE≤-0.50D reference definition yielded 31.0% myopia prevalence. While some definitions resulted in similar prevalence estimates, using the right eye SE of ≤-0.75D; ≤-1.00D or least minus meridian of ≤-0.75D definitions yielded 28.8%, 26.3%, and 26.9% myopia prevalence, respectively, which corresponded to a 7.1%, 15.1% and 13.4% reduction in myopia RR, respectively. The prevalence of high myopia demonstrated considerable alternations, with a 1.7-fold increase in prevalence for the narrower threshold of SE≤-5.00D compared with SE≤-6.00D reference definition (4.2% and 2.4%, respectively). CONCLUSIONS: The prevalence of myopia and especially high myopia varies between frequently applied definitions, considering diverse thresholds, eye lateralization, and spherical vs. astigmatic refractive components. This variability highlights the pressing need for standardization of myopia definition in ophthalmic research. The results of this study provide crude estimates of a "conversion rate" across data, allowing comparisons between studies that utilize different myopia definitions.

B.1.1.7 Variant Outbreak in an Air Force Military Base-Real-World Data.

OBJECTIVE: To assess the clinical features and infectivity of variant B.1.1.7 among healthy young adults in a military setting. MATERIALS AND METHODS: Positive cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a single military base (March 23, 2020 and February 16, 2021) were included. An epidemiological investigation conducted via phone included questions regarding symptoms, exposure history, smoking status, list of contacts, and recently visited places. Symptoms surveyed included fever, cough, shortness of breath, sore throat, loss of smell or taste, gastrointestinal symptoms (GI), headache, chest pain, and constitutional symptoms. Cases were divided before B.1.1.7 first reported case in Israel (December 23, 2020) (period 1) and after its identification (period 2). Symptom distribution and the risk of a contact to be infected were compared between the periods, using a chi-square test, and a negative binominal regression model, respectively. RESULTS: Of 293 confirmed cases, 89 were reported in the first period and 204 in the second. 56.0% were men with a median age of 19.5 years (interquartile range 18.6-20.5). GI symptoms, loss of taste or smell, headache, fever, and chills were more prevalent in the first period (P < .001, P = .026, P = .034, P = .001, and P < .001, respectively), while fatigue was more common in the second period (P = .008). The risk of a contact to be infected was three times higher in the second period (relative risk = 3.562 [2.414-5.258]). CONCLUSION: An outbreak of SARS-CoV-2 in young healthy adults, during a period with high national-wide B.1.1.7 variant prevalence, is characterized by decreased prevalence of fever, loss of taste or smell and GI symptoms, increased reports of fatigue, and more infected contacts for each index case.

SARS-CoV-2 Omicron Variant: Clinical Presentation and Occupational Implications in Young and Healthy IDF Soldiers.

INTRODUCTION: To this date, there is little known about the symptoms, their duration, and occupational implications of Coronavirus disease (COVID-19) in the military population. Decisions regarding implementing precaution measures are based on data deriving from the general population. Moreover, the Omicron variant seems to cause a disease with lesser severity than previous variants. We aimed to describe the clinical presentation and estimate the loss of workdays due to mild COVID-19 during an Omicron predominant wave among a young, healthy, and mostly vaccinated military population. MATERIALS AND METHODS: A cross-sectional, survey-based study among IDF soldiers who replied to an online questionnaire following recovery from COVID-19. Data included self-reported vaccination status, symptoms presentation and duration, and service-related sick days. Student's t-test and chi-square test of independence were used to compare differences in continuous and categorical variables, respectively. A binary logistic regression analysis was performed to estimate the odds ratio and 95% CIs for prolonged symptom duration (4 days and above) by participants' characteristics. The IDF medical corps institutional review board approved this study. RESULTS: A total of 199 soldiers, with a mean age of 21.9 years, were included in the study. Upper respiratory tract symptoms, headache, and constitutional symptoms were found to be the most common among symptomatic soldiers. The median reported time for inability to continue the daily routine, including work, was 5 days [Interquartile range (IQR), 0-10]. Median duration of symptoms was 4 days (IQR, 0-10). In addition, women were found to have longer symptomatic disease (odds ratio = 2.34; 95% CI, 1.20-4.52). CONCLUSIONS: Our findings demonstrate that even among a young and fully vaccinated population, COVID-19 caused by the Omicron variant may result in substantial medical leave from military service, compared to common cold or influenza virus infection. Our study sample was relatively small; however, the response rate was high and our results shed light on the yet-to-be fully characterized Omicron variant-related COVID-19. Despite the current common perception of COVID-19 as a self-limiting mild disease with low burden of symptoms, our findings show the potential occupational burden of infection with COVID-19 on military units and their readiness and could be considered when discussing public health restrictions and further steps taken to minimize outbreaks ramifications.

Adolescent Blood Pressure and the Risk for Early Kidney Damage in Young Adulthood.

BACKGROUND: Recent guidelines classified blood pressure above 130/80 mm Hg as hypertension. However, outcome data were lacking. OBJECTIVE: To determine the association between blood pressure in adolescence and the risk for early kidney damage in young adulthood. METHODS: In this nationwide cohort study, we included 629 168 adolescents aged 16 to 20 who underwent medical examinations before mandatory military service in Israel. We excluded 30 466 adolescents with kidney pathology, hypertension, or missing blood pressure or anthropometric data at study entry. Blood pressure measurements at study entry were categorized according to the Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents: group A (<120/<80 mm Hg; Reference group), group B (120/<80-129/<80 mm Hg), group C (130/80-139/89 mm Hg), and group D (≥140/90 mm Hg). Early kidney damage in young adulthood was defined as albuminuria of ≥30 mg/g with an estimated glomerular filtration rate of 60 mL/(min·1.73 m2) or over. RESULTS: Of 598 702 adolescents (54% men), 2004 (0.3%) developed early kidney damage during a mean follow-up of 15.1 (7.2) years. The adjusted hazard ratios for early kidney damage in blood pressure group C were 1.17 (1.03-1.32) and 1.51 (1.22-1.86) among adolescents with lean (body mass index <85th percentile) and high body mass index (body mass index ≥85th percentile), respectively. Corresponding hazard ratios for kidney disease in group D were 1.49 (1.15-1.93) and 1.79 (1.35-2.38) among adolescents with lean and high body mass index, respectively. CONCLUSIONS: Blood pressure of ≥130/80 mm Hg was associated with early kidney damage in young adulthood, especially in adolescents with overweight and obesity.