Occupational influences on Spondylolysis and Spondylolisthesis in a cohort of 18-year-old male military conscripts.

BACKGROUND: The reported prevalence of spondylolysis (SL) in the adult population is 6-7%. Data concerning adolescent-onset spondylolisthesis (SLS) and the impact of certain activities on it is scarce. We examined the risk of clinical progression of SL and SLS as a function of primary severity and occupational strain among military recruits. METHODS: Based on the Israel defense Force (IDF) central human resources database, we identified 1521 18-year-old males inducted to the IDF with SL/SLS between the late nineteen nineties and early two-thousands. We followed changes in the SL/SLS status during the 3 years of obligatory military service. Disease severity was classified as Cat2: radiological findings of SL without clinical findings; Cat3: painful SL or asymptomatic grade 1 SLS; Cat4: grade 1 SLS with pain; Cat5: Grade 2 SLS. The soldiers were subdivided into the following occupational categories: administrative, combat, maintenance, and driving. The purpose was to compare the progression rates in different medical categories and job assignments. RESULTS: There were 162 recruits in Cat2, 961 in Cat3, and 398 recruits in Cat4. The overall progression rate to Cat5 (grade 2 SLS) was 1.02%. Significant progression rates were seen amongst administrative soldiers with a relatively higher risk of progression from Cat4 (painful-grade-1 SLS: 2.2%) vs. Cat3 (asymptomatic SLS: 0.5%, relative risk = 4.7, p < 0.02). Other occupational categories did not exhibit significant progression rates. CONCLUSION: Progression of SL/SLS was highest in Cat4, i.e. for recruits already diagnosed with painful SLS (i.e. with a more severe baseline disorder). Progression did not correlate with military occupation. We recommend further follow-up studies that include, aside from progression rates, incidence rates of newly diagnosed grade 2 SL during military service.

The association between obesity and secular trend of stature: a nationwide study of 2.8 million adolescents over five decades.

BACKGROUND/OBJECTIVES: It is unclear whether adolescent obesity is associated with limited linear growth. We assessed this association in a nationwide sample of adolescents. METHODS: We conducted a population-based, study of 2,785,227 Israeli adolescents (60% males) who were examined before military service since 1967 through 2015. Height and weight were measured along with assessment of medical status at age 17.4 ± 0.4 years. The secular trend of height was plotted using United States Center for Disease Control (US CDC) age- and sex-adjusted BMI percentile groups. We accounted for health status at enrollment and computed the expected height based on parental data that was available for 512,978 examinees. RESULTS: Over five decades, the mean height increased by 3.1 cm among males, but remained unchanged among females. Among males, gain in height was attained predominantly during the first 25 years and has stabilized since. Males with obesity were taller than their normal-weight and underweight counterparts. Underweight girls had a prominent increase in mean height during the first two decades, exceeding the mean height of their counterparts with obesity by over 2 cm. There was a gradual decrease in the difference between measured and expected height in males and females regardless of BMI status, with the exception of the underweight females who achieved consistently higher stature than expected (≥3 cm). CONCLUSIONS: During five decades, excessive BMI was not a limiting factor in growth potential compared with normal BMI in both sexes. The only group that exceeded its growth potential, when accounting for expected mid-parental height, were underweight females with unimpaired health.

Exploiting the Unique Biology of Caenorhabditis elegans to Launch Neurodegeneration Studies in Space.

The 21st century is likely to be the first century in which large-scale short- and long-term space missions become common. Accordingly, an ever-increasing body of research is focusing on understanding the effects of current and future space expeditions on human physiology in health and disease. Yet the complex experimental environment, the small number of participants, and the high cost of space missions are among the primary factors that hinder a better understanding of the impact of space missions on human physiology. The goal of our research was to develop a cost-effective, compact, and easy-to-manipulate system to address questions related to human health and disease in space. This initiative was part of the Ramon SpaceLab program, an annual research-based learning program designed to cultivate high school students' involvement in space exploration by facilitating experiments aboard the International Space Station (ISS). In the present study, we used the nematode Caenorhabditis elegans (C. elegans), a well-suited model organism, to investigate the effect of space missions on neurodegeneration-related processes. Our study specifically focused on the level of aggregation of Huntington's disease-causing polyglutamine stretch-containing (PolyQ) proteins in C. elegans muscles, the canonical system for studying neurodegeneration in this organism. We compared animals expressing PolyQ proteins grown onboard the ISS with their genetically identical siblings grown on Earth and observed a significant difference in the number of aggregates between the two populations. Currently, it is challenging to determine whether this effect stems from developmental or morphological differences between the cultures or is a result of life in space. Nevertheless, our results serve as a proof of concept and open a new avenue for utilizing C. elegans to address various open questions in space studies, including the effects of space conditions on the onset and development of neurodegenerative diseases.