Smoking initiation among Israeli adolescents: a 24-year time-to-event analysis.

INTRODUCTION: Preventing smoking initiation will protect future generations from smoking-attributable death and disease. This study examines the correlates and patterns of initiation among Israeli youth using time-to-event analysis and other methods. METHODS: Twenty-four consecutive representative samples (1986-2009) of new military recruits (N=50,254) were analyzed. Cox regression and Kaplan-Meier analysis were used to identify factors associated with smoking initiation, and logistic regression was used to identify factors associated with smoking status. RESULTS: The most hazardous age for smoking initiation was seventeen, subsequent to the mean age of smoking initiation (males: 15.7, females: 16.0). Age of initiation and age of greatest hazard for initiation declined among recruits between the years 1986 and 2009. Earlier smoking initiation among boys and girls was significantly associated with low education levels (<12years) (males: HR=2.98, CI: [2.79, 3.18]; females: HR=3.35, CI: [2.96, 3.80]), low paternal education levels, Russian birthplace, and religion. Earlier initiation in boys was associated with high fitness levels and low/medium socio-economic status. Earlier initiation in girls was associated with being Western-born and ever-use of contraception. CONCLUSIONS: Smoking initiation among Israeli youth recruited to the armed forces is associated with individual and family characteristics, particularly low education levels. Time-to-event analysis complements traditional means of understanding smoking initiation by identifying ages at which initiation hazard is high.

Varicocoele among 1 300 000 Israeli adolescent males: time trends and association with body mass index.

Scarce data are available on epidemiology of varicocoele, the most common surgically correctable cause of male infertility. The objectives of this study were to evaluate the association between body mass index (BMI) and varicocoele and to assess trends in prevalence over time. We conducted a nationwide population-based long-term (1967-2010) study among 1 323 061 Israeli adolescent males using data from mandatory medical examination. BMI was grouped into underweight, normal weight, overweight and obese categories by percentiles adjusted for age in months and by further classification to five categories within normal weight. Univariable and multivariable logistic regression models were constructed, adjusting for possible confounders. Varicocoele prevalence (N = 47 398) increased during the study period from 1.6% for the 1950-1954 birth cohort to 4.6% for the 1990-1993 birth cohort, with the steepest rise in the normal weight group. Varicocoele unadjusted rates were highest (4.1%) among underweight and lowest (1.6%) among obese. In a multivariable model, adjusted for birth cohort, height, age and socio-demographic factors, we found a decreased risk for varicocoele in the overweight group [odds ratio (OR) = 0.51, 95% confidence interval (CI): 0.49, 0.54] and the obese group (OR = 0.34, 95% CI: 0.32, 0.37), compared with the normal weight group. Within the normal weight group, a monotonic inverse association between BMI percentile and varicocoele was observed, most notable among 75-84.9 percentile compared to 25-49.9 percentile (OR = 0.65, 95% CI: 0.63, 0.68). In conclusion, varicocoele is common among adolescents in Israel, and its prevalence had increased in recent decades, providing clues to direct further andrological research on the role of modern lifestyle and environment in the aetiology of varicocoele. BMI, across percentiles, was found to be monotonically inversely associated with varicocoele, thus directing research and clinical efforts.

Transmission of Streptococcus pneumoniae in adults may occur through saliva.

Of 742 army recruits tested for pneumococcal nasopharyngeal/oropharyngeal carriage, 6·6% were positive. Frequent sharing of a drinking glass/bottle was a common, strong and independent risk factor for pneumococcal carriage. Our findings strongly suggest, for the first time, that in young adults, transmission of pneumococci may occur via saliva and this should be considered when conducting an outbreak investigation and carriage studies.

Post exposure prophylaxis of tick-borne relapsing fever.

Tick-borne relapsing fever (TBRF) is endemic to Israel. Since 2004, the Israel Defence Forces (IDF) has mandated the prophylaxis of tick-bitten subjects with a five-day doxycycline course. We examined the safety and effectiveness of this policy in preventing TBRF. We analyzed the records from January 2004 to January 2007, and identified all reported events of tick bites or TBRF cases. Data were available on 27 events in which 816 soldiers have undergone physical examination following exposure, and seven TBRF cases were recorded in this group-an attack rate of 0.86% compared with the expected rate of 5.34% from previous army data (relative risk [RR] = 0.16). Of those screened, 128 (15.7%) had tick-bite and were intended for prophylaxis, of which four TBRF cases occurred-3.13% attack rate compared with an expected rate of 38.4% in these bitten individuals without prophylaxis (RR = 0.08, number needed to treat = 3). In all cases in which screening and prophylaxis were provided within 48 h of tick bite, complete prevention of TBRF was achieved. No cases of Jarisch-Herxheimer reaction (JHR) was recorded. Tick-bite screening and prophylactic treatment with doxycycline in endemic areas is a practical, safe, and highly effective policy for preventing TBRF.

Why would young people donate blood? A survey-based questionnaire study.

BACKGROUND AND OBJECTIVES: Different issues associated with blood donation among young donors were studied, towards building a large and consistent blood donor base. METHODS: Data were collected from 221/285 donors in drives conducted among military personnel (response rate of 78%), through a self-administered questionnaire tailored to review knowledge, beliefs, attitudes and habits regarding blood and general donations. Data were then further analysed using a multivariate model. RESULTS: The most significant factors related to blood donation were the donors' perception of approval from a superior (the commander's request to donate blood) and the participant's military rank or position (P < 0.0001 and P = 0.0019, respectively). Experienced blood donors comprised 71.9 % of all donors and more donations were noted among men (P = 0.0013). CONCLUSIONS: The important role of a significant superior, and his or her personal involvement in the blood drive organization was elucidated. Various other factors, previously found to be related to readiness or reluctance to donate blood, were insignificant among the studied population. Our finding may assist blood centres in optimizing their efforts in recruiting and retention of young donors.

Immunity to varicella zoster virus among young adults: a decline prior to widespread uptake of varicella vaccines.

BACKGROUND: The epidemiology of chickenpox in Israel is changing, mainly due to the increasing - but not universal - uptake of varicella vaccine. PATIENTS AND METHODS: We conducted a seroprevalence study of varicella zoster virus (VZV) antibodies among 536 Israeli military recruits 18 years of age, on the basis of a representative sample of sera collected in 2003. RESULTS: The overall seroprevalence rate was 94.6%, which was significantly lower than that observed in a similar population in 1992 (98.4%, p < 0.001). The rate was lower among subjects whose fathers had less than 12 years of schooling (89.8%, p = 0.033). No statistically significant differences were observed when data were stratified by sex, subject's level of education, or origin. CONCLUSION: This decline in the level of immunity must be considered when determining pre- and post-exposure vaccination policy among young adults in crowded environments.