Cross-sectional association between physical activity and serum testosterone levels in US men: results from NHANES 1999-2004.

Testosterone levels and physical activity each play important roles in men's health, but the relationship between the two remains unclear. We evaluated the cross-sectional association between self-reported total physical activity and serum testosterone levels in 738 men (mean age 42.4 years, range 20-≥85 years) who participated in National Health and Nutrition Examination Survey 1999-2004. We compared geometric mean testosterone concentrations measured by radioimmunoassay (RIA) and calculated the odds ratio (OR) of having low or low normal testosterone (≤3.46 ng/mL) across tertiles of total physical activity in all men, and men stratified by age (20-49, ≥50 years), and obesity status (BMI < 30, ≥30 kg/m(2) ). The geometric mean testosterone concentration was 5.31 ng/mL; 18.6% of the men had low or low normal serum testosterone levels. Physical activity tertiles were not associated with testosterone levels overall, or when stratified by age or obesity status. Similarly, there was no association between physical activity tertiles and the odds of low or low normal testosterone, overall or by age. However, among non-obese men, those in the highest physical activity tertile were significantly less likely to have low or low normal testosterone than those in the lowest tertile (OR 0.50; 95% CI = 0.26-0.95); there was no association among obese men. Greater physical activity was not associated with testosterone levels, but may be associated with a reduced odds of low or low normal testosterone in non-obese men, but not in obese men.

Relationships of occupational and non-occupational physical activity to abdominal obesity.

HYPOTHESIS: Physically active occupations may protect against the risk of abdominal obesity. OBJECTIVES: This study assessed the interaction between non-occupational physical activity (NOA) (leisure-time, transport and domestic activity) and occupational activity (OA) in relation to abdominal obesity. METHODS: A total of 3539 adults over the age of 20, with no work limitations, employed in one of the 17 occupations classified as low OA (LOA) or high OA (HOA) were identified in the 1999-2004 National Health and Nutrition Examination Survey. Waist circumference (WC) was used to categorize individuals into either non-obese or abdominally obese (WC>88 cm in women and >102 cm in men) categories. NOA was divided into three categories based upon physical activity guidelines: (1) no NOA; (2) insufficient NOA; and (3) sufficient NOA. Logistic regression was used to examine possible associations between NOA, OA and abdominal obesity. RESULTS: In those who are sedentary outside of work, a high-activity occupation reduces the odds risk ratio of being categorized with abdominal obesity to 0.37 in comparison with those who work in low-activity occupations. For people working in low-activity occupations, there was a clear association with activity outside of work and the odds risk ratio of being categorized with abdominal obesity. In these adults, a reduced odds ratio was found only among those who met the physical activity guidelines through NOA (odds ratio=0.55; 95% confidence interval (CI)=0.40-0.75). CONCLUSION: HOA is associated with a reduced risk of abdominal obesity. Thus, it is important to include OA in studies seeking to understand the association between physical activity and abdominal adiposity.

Relationship of leisure-time physical activity and occupational activity to the prevalence of obesity.

OBJECTIVE: To assess the interaction between leisure-time physical activity (LTPA) and occupational activity (OA) on the prevalence of obesity. DESIGN: Secondary data analysis of a population based cross-sectional US national sample (NHANES III). SUBJECTS: A total of 4889 disease-free, currently employed adults over age 20 y. MEASUREMENTS: Subjects body mass index (BMI) was categorized as (1) obese (BMI> or =30 kg/m(2)), or (2) non-obese (BMI<30 kg/m(2)). LTPA was divided into four categories: (1) no LTPA; (2) irregular LTPA; (3) regular moderate intensity LTPA; and (4) regular vigorous intensity LTPA. OA was grouped as (1) high OA and (2) low OA. Age, gender, race-ethnicity, smoking status, urbanization classification, alcohol consumption and income were statistically controlled. RESULTS: In all, 16.8% (s.e. 0.7) of the total subject population were obese (15.1% (s.e. 1.1) of men and 19.1% (s.e. 1.1) of women). Logistic regression revealed that compared to those who engage in no LTPA and have low levels of OA, the likelihood of being obese is 42% (95% CI 0.35, 0.96) lower for those who engage in no LTPA and have high OA, 48% (95% CI 0.32, 0.83) lower for those who have irregular LTPA and have high levels of OA, and about 50% lower for all those who have regular LTPA through moderate or vigorous activity levels regardless of OA level. CONCLUSION: When considering disease free adults above 20 y of age employed in high and low activity occupations, a high level of occupational activity is associated with a decreased likelihood of being obese.

Smoking acquisition: peer influence and self-selection.

The study examined and contrasted the extent that peer influence and self-selection for smoking peers may affect acquisition of smoking by adolescents. Data for a U.S. national cohort sample of adolescents (N = 4,444) who were nonsmokers in the 1989 Teenage Attitudes and Practices Surveys and were re-interviewed in 1993 were included. The information included measures of smoking behavior and smoking status of both boys' and girls' best friends. Analysis demonstrated that, although the effects of both peer influence and self-selection of smoking friends occurred, self-selection may play a greater role in adolescents' beginning to smoke. This implies that, while teaching adolescents to resist peer pressure may be necessary, it is perhaps more important to identify factors that influence adolescents' decisions in choosing friends who smoke. This could lead to more effective preventive strategies.

Controlled drug misuse by Certified Registered Nurse Anesthetists.

The primary purpose of this study was to determine the prevalence of controlled drug misuse among actively practicing Certified Registered Nurse Anesthetists (CRNAs). A second purpose was to determine variance in controlled drug misuse by the variables of age, sex, population and geographic area of residence, type of anesthesia position currently held, and number of years in anesthesia practice. The research data were obtained through self-administered surveys mailed to 2,500 actively practicing CRNAs throughout the United States. With a response rate of 68.4% (1,709 of 2,500), the survey instrument allowed for stratification according to admitted misuse of controlled drugs commonly used in the clinical practice of anesthesia. The established prevalence of controlled drug misuse in the target population was found to be 9.8% of the sample (167 of 1,709 respondents), with the majority indicating a distinct proclivity for polydrug misuse. The survey results were comparable with those of studies involving anesthesiologists and registered nurses with the notable exception of the preferred drugs for misuse. A strong relationship existed between sex, number of years in clinical anesthesia practice, and the likelihood for controlled drug misuse, thus indicating a potential predictor of which CRNAs may misuse controlled drugs. In addition, a significant relationship existed between recency of controlled drug misuse and drug(s) of choice (P = .05). Recommendations include specific tactics for strengthening drug misuse education and prevention. Also, modifications in research design and additional studies in the research area are suggested.

Prospective social-psychological factors of adolescent smoking progression.

PURPOSE: To evaluate the ability of social-psychological risk factors to predict adolescent smoking behavior. METHODS: Nonsmoking adolescents (n = 4032) who participated in the 1989 and 1993 Teenage Attitudes and Practices Surveys (TAPS I) were selected for analyses. Four multivariate logistic models were used to examine (a) adolescents' smoking initiation, (b) adults' smoking initiation, (c) adolescents' progression to regular smoking, and (d) adults' progression to regular smoking. A series of social-psychological variables were measured. RESULTS: All four models were significant. However, no social-psychological factors were consistently significant in all four models, except white ethnicity. Data showed that social-psychological factors are less able to predict the transition from nonsmoking to experimental smoking than that from nonsmoking to regular smoking. CONCLUSIONS: Future prospective studies should measure both social-psychological and smoking acquisition factors at closer intervals to more accurately examine potential relationships.

School dropouts' attitudes and beliefs about smoking.

The purpose of this study was to examine the association of beliefs and attitude related to smoking and smoking behavior among school dropouts in a national sample (weighted N = 492,352). The self-reported smoking rate for school dropouts was 58.3%. Those who were most positive about smoking (such as smoking helps people reduce stress and relax, reduce boredom) were more likely to be smokers (p < .05). Smoking programs targeting this population should provide coping skills and an environment with options for relaxing, managing stress, and safe weight control.

Social influence on southern adolescents' smoking transition: a retrospective study.

The purpose of this study was to examine social factors that predicted adolescent smoking transition to more advanced stages of smoking behavior during a 3-year span. A national cohort sample of adolescents (N = 2,099) who participated in the 1989 and 1993 Teenage Attitudes and Practices Survey (TAPS I and TAPS II, respectively) was used for this study. The information obtained from this survey included measurements of smoking behavior and a series of factors related to smoking models in the respondents' social environment, such as smoking behavior of parents, siblings, and best friends. Results showed that the smoking behavior of an adolescent's best male friend was consistently associated with transition from nonsmoking to regular smoking and from experimental smoking to regular smoking. The most surprising finding was that the study showed no relationship between social influence and transition from nonsmoking to experimental smoking.

The impact of worksite-based safety belt programs: a review of the literature.

PURPOSE: The purpose of this paper is to provide a literature review of the research that examines the effectiveness of worksite intervention programs designed to increase the use of safety belts by employees. SEARCH METHODS: The literature search, which identified 14 research studies on worksite safety belt programs conducted between 1968 and 1994, originated as part of a larger review on the health impact of worksite health promotion programs that was conducted by the Centers for Disease Control and Prevention (CDC). In addition, the authors conducted an additional search in an effort to validate the CDC search, but found no additional research articles. SUMMARY OF IMPORTANT FINDINGS: The literature specific to the effectiveness of safety belt programs is limited to only 14 studies. The safety belt intervention most commonly evaluated used behavioral modification principles involving incentives. These and other interventions demonstrated effective increases in seat belt utilization that, upon withdrawal of the intervention, achieved a recidivism rate above baseline levels. However, the vast majority of studies failed to incorporate control groups into their research design, which caused significant threats to internal validity. Thus, a summary of findings is only suggestive at best. MAJOR CONCLUSIONS: Based on the literature, there appears to be an insufficient number of quality research studies from which to derive a clear view of the impact of worksite safety belt programs. While the evidence is suggestive of a positive impact on safety belt use, there is a clear need for new, well-designed research initiatives on the effectiveness of theory-based safety belt intervention programs.

Sociobehavioral influences on smoking initiation of Hispanic adolescents.

PURPOSE: To study the sociobehavioral influences on smoking initiation of Hispanic adolescents over a 3-year period using a national sample. METHODS: Hispanic adolescents (N = 385), ages 15-22 years, from the 1989 and 1993 Teenage Attitudes and Practices Surveys (TAPS I and II), were selected for analyses. Data collected included measures of smoking initiation and attitudes, beliefs toward smoking of the adolescent, and smoking status of family and peers. RESULTS: At the 3-year follow up, 43.4% of nonsmokers at TAPS I had initiated smoking. Risk factors associated with initiating smoking were having male and/or female friends who smoked, and positive attitudes and beliefs towards smoking. Parental and sibling smoking status had little effect on adolescent smoking status. CONCLUSIONS: The peer influence on Hispanic adolescent smoking is consistent with previous research on Caucasian and African-American adolescents. The formation of attitudes and beliefs toward smoking in this population warrants further examination given the influence of attitudes and beliefs on smoking initiation in this study.

Association of depressive symptoms and school adolescents' smoking: a cross-lagged analysis.

This study examined the association of depressive symptoms of adolescents and their smoking behavior. A national cohort sample of school adolescents (N = 5,855) who participated in the 1989 and 1993 Teenage Attitudes and Practices Survey was obtained. The information from this survey included measures of smoking behavior and a series of factors related to depressive symptoms during a 3-yr. span. A cross-lagged analysis with Kendall tau b correlations was used. Judging from the magnitude of the cross-lagged correlations, the direction of causation cannot be ascertained. Rather, a reciprocal relationship between depression and smoking may be suggested.

Physiological sensations of initial smoking in the development of regular smoking behavior.

This study examined the relationships between adolescents' physiological sensations of smoking during initiation and early experience. For a national sample of a birth cohort of 2,043 adolescents, ages 15 to 22 years at the follow-up, variables of interest included measures of smoking behavior and physiological sensations reported from the initial smoking experience. Analysis showed that adolescents experimenting with smoking were more likely to become regular smokers over three years if they indicated that they felt relaxed, felt dizzy, did not feel sick, and did not cough during the initial smoking experience. Antismoking interventions may impede the transition to regular smoking by helping adolescents interpret the physiological sensations as negative and unhealthy.

Developmental influences of attitudes and beliefs on adolescents' smoking.

This study examined developmental influences of beliefs and attitudes on adolescents' smoking. A national sample (N = 6,900) of adolescents ages 14 to 18 was selected. Data included measures of smoking behavior, beliefs, and attitudes. Although odds ratios show that attitudes and beliefs are predictive of adolescents' smoking status across the ages of 14 to 18 years, no systematic change of the prediction is evident, which contrasts with the psychological developmental model.

Family and peer influences on smoking behavior among American adolescents: an age trend.

PURPOSE: To study the age trend of family and peer influence on adolescent smoking behavior using a national sample. METHODS: Adolescents (N = 6,900), ages 14 through 18 years, from the 1988-89 Teenage Attitudes and Practices Survey, were selected for analyses. Data collected included measures for smoking status of the adolescent and their family and peers. RESULTS: Peer influence, such as the smoking status of best male/female friends, proved to be the most significant and consistent predictor across all ages, while parental influence had little effect on adolescent smoking status. Gender-specific effects were noted in the peer influence of adolescent smoking. CONCLUSIONS: The peer influence on adolescent smoking, across ages 14 through 18 years, confirmed previous literature. However, no differential effect of family and peer influence on adolescent smoking was evident.

The acute effect of moderate alcohol consumption on cardiovascular responses in women.

OBJECTIVE: The purpose of this study was to assess the effects of moderate dose alcohol consumption on human metabolic and cardiovascular responses during submaximal exercise. METHOD: Ten female subjects participated in two experimental conditions: (1) an alcohol session where the subjects ingested 0.625 g per kg body weight of 80-proof ethyl alcohol (0.25 g/kg of 100% ethanol), and (2) a placebo session. In each session, the subjects exercised on a stationary bicycle at 70% predicted maximum heart rate (HR) for 30 minutes. HR, blood pressure (BP) and oxygen consumption (VO2) were measured at the baseline and at 10, 20 and 30 minute intervals during exercise. Blood lactic acid (BLA) was measured at the baseline and at the end of exercise. RESULTS: Repeated analysis of variance and subsequent comparisons showed that the alcohol session had significantly higher scores for HR, BP, VO2 and BLA than the placebo session (p < .05). CONCLUSIONS: These results suggest that during submaximal work, acute moderate alcohol consumption may interfere with aerobic energy metabolism, thus increasing the demand placed upon the cardiovascular system.

Southern adolescents: a survey of attitudes and beliefs about smoking.

Using data collected by the National Center for Health Statistics, we examined the relationships between smoking-related beliefs and attitudes and smoking status for a sample of adolescents (N = 3,198) from southern states. Stepwise logistic regression was used to identify the best predictors of smoking prevalence. Results indicated that 8 of 13 variables in the logistic model significantly differentiated between smokers and nonsmokers. Smokers were more likely to believe that it is safe to smoke for only a year or 2 and that smoking helps reduce stress and boredom while promoting relaxation. Smokers also reported a higher tolerance than nonsmokers for being around other smokers, and reported their parents would not mind their smoking. The logistic model attained a predictive accuracy of 93.2%. The implication of these findings is that if smoking interventions targeted at adolescents address smoking-related beliefs and attitudes, there is an enhanced likelihood that such interventions will positively influence the smoking behavior of southern adolescents.

Predicting smoking status by symptoms of depression for U.S. adolescents.

This study examined the predictive relationships between adolescents' smoking and symptoms of depression. A national sample of 6,900 adolescents, ages 14 to 18 years, were selected for analysis. Variables of interest included measures for smoking status and symptoms of depression. Odds ratio and adjusted odds ratio from logistic regression analyses indicated that more of the 885 smokers than of the 6,015 nonsmokers reported feelings of unhappiness, sadness, or depression, hopelessness about the future, and having trouble going to sleep.

Tobacco use among American adolescents: geographic and demographic variations.

A previous national study indicated that the South dominated other regions of the United States in tobacco use. Using the results of the Teenage Attitudes and Practices Survey conducted by the National Center for Health Statistics, we examined the geographic and demographic differences of tobacco use among US adolescents. The sample consisted of teenagers in grades 7 through 12 nationwide (N = 6,599). Data were collected through telephone interviewing. The variables included demographics and measures of smoking or use of smokeless tobacco (chewing tobacco/snuff). Results indicated that the overall prevalence rate for smokeless tobacco use was 4.44%, but in the South it was 6.38%. The overall smoking prevalence rate was 13.31%, with no substantial difference among regions. Demographic variables such as sex, ethnicity, education, and poverty levels were also related to tobacco use prevalence. These geographic and demographic variations in tobacco use help target specific regions and populations in greatest need of intervention programs.

Desire for weight gain and potential risks of adolescent males using anabolic steroids.

This study examined the perceptions of adolescent males regarding their physical strength, health status, and desire to gain weight and their perceptions of anabolic steroid use. Subjects were 12th-grade boys (N = 3403), drawn from a pool of 150 high schools nationwide, who completed a health questionnaire. Analysis indicated 47.0% (n = 1475) who wanted to gain weight, perceived themselves as of less than average strength and having good health, and were sports participants. Also, among those who desired weight gain, about 24% (n = 345) were not sure about the most dangerous health risks associated with anabolic steroid use, and 16% (n = 221) did not want to see the use of anabolic steroids in sports stopped. The findings indicate that adolescent boys, who desired weight gain and currently abstained from anabolic steroid use, might be at risk for becoming users.

The effects of high and low BACs on the Hoffmann reflex.

The purpose of this study was to measure and assess the magnitude and latency of the H-reflex and M-response between pre- and post-alcohol consumption. Also of interest was the comparison of the H-reflex and M-response between the rising and falling curves of BAC. Seven male volunteer subjects participated in this study. Testing started with pre-alcohol BAC and EMG recordings from the tibial nerve following an electrical stimulation. After alcohol consumption, BAC readings were obtained every five minutes, and the EMGs were recorded at the following BAC levels (in mg/dl): 75, 100, and falling 75. H-latency, H-amplitude, and M-response were identified within the EMG signals. The analysis focused on the comparisons of these measures between each of the BAC levels and the baseline, as well as between the rising and falling BACs. Results showed that, overall, the H-reflex and M-response were depressed following alcohol consumption. In addition, the depression of H-reflex appeared to be greater during the rising curve than the falling curve.