Jonathan D.S. Klein

Learn More
OBJECTIVE To determine the extent to which the 2007 definitions for severe obesity (body mass index [BMI] > or = 99th percentile for age and gender) and morbid obesity (BMI > or = 40kg/m(2)) affects different groups of American children and adolescents and has increased over time. METHODS Analysis of nationally representative data from the National Health(More)
OBJECTIVES We assessed trends in use of electronic cigarettes among U.S. adults, demographic predictors of use, and smoking status of current electronic cigarette users. METHODS Mixed-mode surveys were used to obtain representative, cross-sectional samples of U.S. adults in each of 4 years. RESULTS Sample sizes for 2010, 2011, 2012, and 2013 were 3,240,(More)
The internet is one of a range of health information sources available to adolescents. It is recognised that young people have difficulties accessing traditional health services; in theory, the internet offers them confidential and convenient access to an unprecedented level of information about a diverse range of subjects. This could redress adolescents'(More)
The prevention of unintended adolescent pregnancy is an important goal of the American Academy of Pediatrics and our society. Although adolescent pregnancy and birth rates have been steadily decreasing, many adolescents still become pregnant. Since the last statement on adolescent pregnancy was issued by the Academy in 1998, efforts to prevent adolescent(More)
PURPOSE Set-shifting is a neurocognitive concept defined as the ability to switch tasks flexibly. Set-shifting scores are worse in adults with restrictive anorexia nervosa (AN-R) than in controls. Adolescence is a developmental period when young people must respond flexibly to new situations. The purpose of this study was to compare the set-shifting scores(More)
OBJECTIVE The belief that college students gain 15 lbs during freshman year is widespread, yet the evidence for this is limited. The authors aimed to determine whether college students gain weight during freshman year. PARTICIPANTS The authors studied unmarried freshmen living on-campus at a private university in the northeastern United States. METHODS(More)
PURPOSE Use of complementary and alternative medicine (CAM) is increasing, but some dietary supplements have potentially negative side effects. This study examines CAM and dietary supplement use among a national sample of adolescents. METHODS A total of 1280 adolescents 14-19 years old completed an online survey in 2002 about lifetime and past-30-day use(More)
PURPOSE To evaluate factors that independently predict counseling for diet, exercise, sexually transmitted diseases (STDs), pregnancy, smoking, and injuries at adolescent well visits, and compare these rates to the frequency of counseling at adolescent acute visits. METHODS The 1997-2000 National Ambulatory Medical Care and National Hospital Ambulatory(More)
OBJECTIVE The purpose of this study was to examine pediatrician implementation of BMI and provider interventions for childhood overweight prevention and treatment. METHODS Data were obtained from the American Academy of Pediatrics (AAP) Periodic Survey of Fellows No. 65, a nationally representative survey of AAP members. Surveys that addressed the(More)
OBJECTIVE To determine the longitudinal effect of abuse by an intimate partner on risk behavior among adolescents. DESIGN AND PARTICIPANTS Linear regression analyses of longitudinal data from 4443 adolescents surveyed in 1995 (Wave I) and 1996 (Wave II) from the National Longitudinal Study of Adolescent Health Public Use Dataset. MAIN OUTCOME MEASURES(More)