Mandibular muscle troponin of the Florida carpenter ant Camponotus floridanus: extending our insights into invertebrate Ca2+ regulation.

Ants use their mandibles for a variety of functions and behaviors. We investigated mandibular muscle structure and function from major workers of the Florida carpenter ant Camponotus floridanus: force-pCa relation and velocity of unloaded shortening of single, permeabilized fibres, primary sequences of troponin subunits (TnC, TnI and TnT) from a mandibular muscle cDNA library, and muscle fibre ultrastructure. From the mechanical measurements, we found Ca2+-sensitivity of isometric force was markedly shifted rightward compared with vertebrate striated muscle. From the troponin sequence results, we identified features that could explain the rightward shift of Ca2+-activation: the N-helix of TnC is effectively absent and three of the four EF-hands of TnC (sites I, II and III) do not adhere to canonical sequence rules for divalent cation binding; two alternatively spliced isoforms of TnI were identified with the alternatively spliced exon occurring in the region of the IT-arm α-helical coiled-coil, and the N-terminal extension of TnI may be involved in modulation of regulation, as in mammalian cardiac muscle; and TnT has a Glu-rich C-terminus. In addition, a structural homology model was built of C. floridanus troponin on the thin filament. From analysis of electron micrographs, we found thick filaments are almost as long as the 6.8 µm sarcomeres, have diameter of ~ 16 nm, and typical center-to-center spacing of ~ 46 nm. These results have implications for the mechanisms by which mandibular muscle fibres perform such a variety of functions, and how the structure of the troponin complex aids in these tasks.

Estimating causal and time-varying effects of maternal smoking on youth smoking.

INTRODUCTION: Maternal smoking is a well-known risk factor for youth smoking, yet whether this relationship is causal remains unresolved. This study utilizes propensity score methods for causal inference to robustly account for shared risk factors between maternal and offspring smoking. METHODS: An 8-year longitudinal cohort of 900 adolescents in the Chicago area were followed starting from approximately age 15.6. The effects of maternal lifetime smoking (MLS) and prenatal tobacco exposure (PTE) (among participants reporting MLS) on offspring's past 30-day smoking, daily smoking status and smoking frequency were examined using logistic regression and Poisson regression after nearest-neighbor propensity matching. Age dependency of this relationship was then examined across the age range of 15-25 using time-varying effect modeling. RESULTS: Propensity matching yielded 438 and 132 pairs for MLS and PTE study samples, respectively. MLS demonstrated significant associations with past 30-day smoking (RR 1.09; 95% CI 1.04-1.14), daily smoking (RR 1.08; 95% CI 1.05-1.12), and smoking frequency of offspring (RR 1.32; 95% CI 1.15-1.52), with stable effects across age. Among participants reporting MLS, having PTE showed significant additional effects on daily smoking (RR 1.09; 95% CI 1.02-1.17) and age-dependency that showed significance during young adulthood but not adolescence. CONCLUSION: The relationship between maternal and offspring smoking was not fully accounted for by shared risk factors, suggesting possible causation with PTE having a delayed effect across age. Targeted prevention efforts should be made on maternal smoking-exposed adolescents to mitigate their risks of developing heavy smoking habits in adulthood.

The Effect of Maternal Smoking on Offspring Smoking Is Unrelated to Heritable Personality Traits or Initial Subjective Experiences.

INTRODUCTION: Maternal smoking is a risk factor for offspring smoking. Lifetime maternal smoking vs. prenatal tobacco exposure (PTE) appears to act through different mechanisms. This study tested the hypothesis that maternal smoking measures' effects on offspring smoking could be attributable to hereditary mechanisms: personality traits (novelty-seeking, impulsivity, neuroticism, and self-esteem) and initial subjective smoking experiences (pleasurable, unpleasurable, and dizziness). METHODS: Data were drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns study, an 8-year longitudinal study of 9th or 10th graders at baseline (≈age 15) who experiment with smoking (<100 lifetime cigarettes; N = 594) at baseline. The young adult smoking frequency at the 8-year follow-up (≈age 23) was examined as a function of baseline characteristics (heritable trait, maternal smoking, PTE, and sex) and baseline smoking frequency and nicotine dependence. Structural equation models determined whether the inclusion of each heritable trait among offspring confounded the effects of maternal smoking (PTE or maternal smoking) on offspring smoking and nicotine dependence. RESULTS: Impulsiveness was associated with intermediate adolescent smoking frequency (B = 0.135, SD = 0.043, p = .002) and nicotine dependence (B = 0.012, SD = 0.003, p < .001). Unpleasurable first experience (B = 0.886, SD = 0.374, p = .018) and dizziness (B = 0.629, SD = 0.293, p = .032) showed a trend with intermediate smoking frequency that was nonsignificant after correcting for multiple comparisons. These traits did not confound maternal smoking's effects. CONCLUSIONS: None of the heritable traits examined in this model explained the effect of maternal smoking measures on adolescence or young adulthood offspring smoking. Further research is needed to elucidate the mechanism by which PTE and maternal smoking are linked to offspring smoking. IMPLICATIONS: Prenatal tobacco exposure (PTE) and mother's lifetime smoking present separate and independent risks for offspring smoking; however, their mechanisms seem unrelated to heritable personality traits and initial subjective smoking experiences. These findings have implications for separate screening strategies tailored to different age groups, especially related to PTE's risk of smoking in young adulthood. Additionally, these findings add to the known risks of maternal smoking. Further research is needed to understand the mechanism underlying the risk posed by maternal lifetime smoking and PTE on offspring smoking behavior.

Use of noninvasive positive pressure ventilation in patients with severe obesity undergoing esophagogastroduodenoscopy: a randomized controlled trial.

BACKGROUND: Patients with severe obesity being considered for bariatric surgery often undergo preoperative esophagogastroduodenoscopy (EGD). Severe obesity is a risk factor for oxygen desaturation events during EGD. The use of noninvasive positive pressure ventilation (NIPPV) to reduce desaturation events during EGD among patients with severe obesity has not been studied. OBJECTIVE: To evaluate the use of NIPPV among patients with severe obesity undergoing EGD. SETTING: Community hospital endoscopy suite. METHODS: A randomized controlled trial evaluated the use of NIPPV in patients with severe obesity undergoing EGD. Patients were randomized into treatment (NIPPV) and control (nasal cannula, NIPPV for rescue) groups. Primary endpoints were oxygen desaturation events ≤94% and oxygen desaturation events <90% requiring intervention. A secondary endpoint was the use of NIPPV as a rescue maneuver. RESULTS: Fifty-six patients with a body mass index of 40 to 60 were randomized (n = 28 treatment and n = 28 control). A statistically significant difference was noted between the groups for desaturation events ≤94% (14.3% of treatment and 57.1% of control groups, P = .002). There was also a statistically significant difference in the risk of a desaturation event <90% requiring intervention (3.5% of treatment and 28.6% of control groups, P = .025). All patients in the control group who developed desaturation events requiring intervention were rescued with NIPPV. CONCLUSIONS: This study demonstrated the successful use of NIPPV as an adjunct to decrease the incidence of desaturation events in patients with severe obesity undergoing EGD.

The role of nicotinic receptor genes (CHRN) in the pathways of prenatal tobacco exposure on smoking behavior among young adult light smokers.

BACKGROUND: Prenatal tobacco exposure (PTE) is associated with more frequent smoking among young, light smokers. Little is known about how nicotinic acetylcholine receptor (CHRN) genes may contribute to this relationship. METHODS: Data were drawn from a longitudinal cohort of young light smokers of European ancestry (N = 511). Three single nucleotide polymorphisms (SNPs) among offspring, rs16969968 and rs6495308 in CHRNA5A3B4 and rs2304297 in CHRNB3A6, were analyzed with respect to whether they 1) predict PTE status; 2) confound the previously-reported effects of PTE on future smoking; 3) have effects on youth smoking frequency that are mediated through PTE; and 4) have effects that are moderated by PTE. RESULTS: rs2304297 and rs6495308 were associated with increased likelihood and severity of PTE, respectively. In a path analysis, rs16969968 directly predicted more frequent smoking in young adulthood (B = 1.50, p = .044); this association was independent of, and not mediated by, PTE. The risk of rs16969968 (IRR = 1.07, p = .015) and the protective effect of rs2304297 (IRR = 0.84, p < .001) on smoking frequency were not moderated by PTE. PTE moderated the effect of rs6495308, such that these alleles were protective against later smoking frequency only among non-exposed youth (IRR = 0.85, p < .001). CONCLUSIONS: The association between offspring CHRNB3A6 and PTE is a novel finding. The risk of rs16969968 on youth smoking is independent and unrelated to that of PTE among young, light smokers. PTE moderates the protective effect of rs6495308 on youth smoking frequency. However, PTE's pathway to youth smoking behavior was not explained by these genetic factors, leaving its mechanism(s) of action unclear.

Integrative Data Analysis of Gender and Ethnic Measurement Invariance in Nicotine Dependence Symptoms.

Little research has evaluated whether conflicting evidence for gender and racial/ethnic differences in nicotine dependence (ND) may be attributed to differences in psychometric properties of ND symptoms, particularly for young Hispanic smokers. Inadequate racial/ethnic diversity and limited smoking exposure variability has hampered research in young smokers. We used integrative data analysis (IDA) to pool DSM-IV ND symptom data for current smokers aged 12-25 (N = 20,328) from three nationally representative surveys (1999, 2000 National Surveys on Drug Use and Health (NSDUH) and Wave 1 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Moderated nonlinear factor analysis (MNLFA) tested symptom measurement invariance in the pooled sample containing greater ethnic and smoking exposure variability. There was study noninvariance for most symptoms. NESARC participants were more likely to report tolerance, using larger amounts or for longer periods, inability to cut down/quit, and more time spent smoking at higher levels of ND severity, but reported emotional/physical health problems at lower ND severity. Four symptoms showed gender or race/ethnicity noninvariance, but observed differences were small. An ND severity factor score adjusting for symptom noninvariance related to study membership, gender, and race/ethnicity did not differ substantively from traditional DSM-IV diagnosis and number of endorsed symptoms in estimated gender and race/ethnicity differences in ND. Results were consistent with studies finding minimal gender and racial/ethnic differences in ND, and suggest that symptom noninvariance is not a major contributor to observed differences. Results support IDA as a potentially promising approach for testing novel ND hypotheses not possible in independent studies.

A Network Analysis of Sexually Transmitted Diseases and Online Hookup Sites Among Men Who Have Sex With Men.

BACKGROUND: Sexually transmitted diseases (STDs) are increasing among gay, bisexual, and other men who have sex with men (MSM). Little is known about the use of websites and mobile phone applications to meet sexual partners ("hookup sites") and association with STD diagnoses. METHODS: We performed a demographic and behavioral assessment of 415 MSM presenting to the Rhode Island STD clinic. Bivariate and multivariable analyses assessed associations between using hookup sites and testing positive for syphilis, gonorrhea, or chlamydia. Venue-based affiliation networks were created to evaluate hookup sites and their association with STD diagnoses. RESULTS: Among 415 MSM, 78% reported meeting a partner online in the last 12 months, and 25% tested positive for at least one STD. Men who met partners online were more likely to be white (67% vs. 54%, P = 0.03) and have more than 10 lifetime partners (87% vs. 58%, P < 0.05). The most commonly used hookup sites included Grindr (78%), Scruff (35%), and Tinder (22%). In the multivariable analysis, only Scruff use was associated with testing positive for an STD (odds ratio, 2.28; 95% confidence interval, 1.09-4.94). However, among men who met partners online, 75% of men diagnosed as having an STD had met a sexual partner on Grindr, including 100% of those who were diagnosed as having gonorrhea. CONCLUSIONS: Use of hookup sites was nearly ubiquitous among MSM undergoing STD screening. Specific hookup sites were significantly associated with STD diagnoses among MSM. Greater efforts are needed to promote STD screening and prevention among MSM who meet partners online.

Evaluating the mutual pathways among electronic cigarette use, conventional smoking and nicotine dependence.

BACKGROUND AND AIMS: The implications of the rapid rise in electronic cigarette (e-cigarette) use remain unknown. We examined mutual associations between e-cigarette use, conventional cigarette use and nicotine dependence over time to (1) test the association between e-cigarette use and later conventional smoking (both direct and via nicotine dependence), (2) test the converse associations and (3) determine the strongest pathways predicting each product's use. DESIGN: Data from four annual waves of a prospective cohort study were analyzed. Path analysis modeled the bidirectional, longitudinal relationships between past-month smoking frequency, past-month e-cigarette frequency and nicotine dependence. SETTING: Chicago area, Illinois, USA. PARTICIPANTS: A total of 1007 young adult smokers and non-smokers (ages 19-23 years). MEASUREMENTS: Frequency of (1) cigarettes and (2) e-cigarettes was the number of days in the past 30 on which the product was used. The Nicotine Dependence Syndrome Scale measured nicotine dependence to cigarettes. FINDINGS: E-cigarette use was not associated significantly with later conventional smoking, either directly (ß = 0.021, P = 0.081) or through nicotine dependence (ß = 0.005, P = 0.693). Conventional smoking was associated positively with later e-cigarette use, both directly (ß = 0.118, P < 0.001) and through nicotine dependence (ß = 0.139, P < 0.001). The strongest predictors of each product's use was prior use of the same product; this pathway was strong for conventional cigarettes (ß = 0.604, P < 0.001) but weak for e-cigarettes (ß = 0.120, P < 0.001). Nicotine dependence moderately strongly predicted later conventional smoking (ß = 0.169, P < 0.001), but was a weak predictor of later e-cigarette use (ß = 0.069, P = 0.039). CONCLUSIONS: Nicotine dependence is not a significant mechanism for e-cigarettes' purported effect on heavier future conventional smoking among young adults. Nicotine dependence may be a mechanism for increases in e-cigarette use among heavier conventional smokers, consistent with e-cigarettes as a smoking reduction tool. Overall, conventional smoking and, to a lesser extent, its resulting nicotine dependence, are the strongest drivers or signals of later cigarette and e-cigarette use.

The Role of Nicotine Dependence in E-Cigarettes' Potential for Smoking Reduction.

Introduction: E-cigarettes (Electronic Nicotine Delivery Systems, or ENDS) are an increasingly popular tobacco product among youth. Some evidence suggests that e-cigarettes may be effective for harm reduction and smoking cessation, although these claims remain controversial. Little is known about how nicotine dependence may contribute to e-cigarettes' effectiveness in reducing or quitting conventional smoking. Methods: A cohort of young adults were surveyed over 4 years (approximately ages 19-23). Varying-coefficient models (VCMs) were used to examine the relationship between e-cigarette use and conventional smoking frequency, and how this relationship varies across users with different nicotine dependence levels. Results: Lifetime, but not recent, e-cigarette use was associated with less frequent concurrent smoking of conventional cigarettes among those with high levels of nicotine dependence. However, nondependent e-cigarette users smoked conventional cigarettes slightly more frequently than those who had never used e-cigarettes. Nearly half of ever e-cigarette users reported using them to quit smoking at the last measurement wave. For those who used e-cigarettes in a cessation attempt, the frequency of e-cigarette use was not associated with reductions in future conventional smoking frequency. Conclusions: These findings offer possible support that e-cigarettes may act as a smoking reduction method among highly nicotine-dependent young adult cigarette smokers. However, the opposite was found in non-dependent smokers, suggesting that e-cigarette use should be discouraged among novice tobacco users. Additionally, although a substantial proportion of young adults used e-cigarettes to help them quit smoking, these self-initiated quit attempts with e-cigarettes were not associated with future smoking reduction or cessation. Implications: This study offers potential support for e-cigarettes as a smoking reduction tool among highly nicotine-dependent young adult conventional smokers, although the extent and nature of this remains unclear. The use of e-cigarettes as a quit aid was not associated with reductions in conventional smoking, consistent with most other quit aids in this sample except for nicotine replacement therapy, which was only effective for the most dependent smokers. Notably, these findings highlight the necessity of accounting for smokers' nicotine dependence levels when examining tobacco use patterns.

Early-Emerging Nicotine Dependence Has Lasting and Time-Varying Effects on Adolescent Smoking Behavior.

Novice and light adolescent smokers can develop symptoms of nicotine dependence, which predicts smoking behavior several years into the future. However, little is known about how the association between these early - emerging symptoms and later smoker behaviors may change across time from early adolescence into young adulthood. Data were drawn from a 7-year longitudinal study of experimental (<100 cigarettes/lifetime; N = 594) and light (100+ cigarettes/lifetime, but ≤5 cigarettes/day; N = 152) adolescent smokers. Time-varying effect models were used to examine the relationship between baseline nicotine dependence (assessed at age 15 ± 2 years) and future smoking frequency through age 24, after controlling for concurrent smoking heaviness. Baseline smoking status, race, and sex were examined as potential moderators of this relationship. Nicotine dependence symptoms assessed at approximately age 15 significantly predicted smoking frequency through age 24, over and above concurrent smoking heaviness, though it showed declining trends at older ages. Predictive validity was weaker among experimenters at young ages (<16), but stronger at older ages (20-23), relative to light smokers. Additionally, nicotine dependence was a stronger predictor of smoking frequency for white smokers around baseline (ages 14.5-16), relative to nonwhite smokers. Nicotine dependence assessed in mid-adolescence predicts smoking frequency well into early adulthood, over and above concurrent smoking heaviness, especially among novice smokers and nonwhite smokers. Early-emerging nicotine dependence is a promising marker for screening and interventions aimed at preventing smoking progression.

Individual and Partner-Level Factors Associated with Condom Non-Use Among African American STI Clinic Attendees in the Deep South: An Event-Level Analysis.

The US HIV/AIDS epidemic is concentrated in the Deep South, yet factors contributing to HIV transmission are not fully understood. We examined relationships between substance use, sexual partnership characteristics, and condom non-use in an African American sample of STI clinic attendees in Jackson, Mississippi. We assessed condom non-use at last intercourse with up to three recent sexual partners reported by participants between January and June 2011. Participant- and partner-level correlates of condom non-use were examined using generalized estimating equations. The 1295 participants reported 2880 intercourse events, of which 1490 (51.7 %) involved condom non-use. Older age, lower educational attainment, reporting financial or material dependence on a sex partner, sex with a primary partner, and higher frequency of sex were associated with increased odds of condomless sex. HIV prevention efforts in the South should address underlying socioeconomic disparities and structural determinants that result in partner dependency and sexual risk behavior.

Results from a Geographically Focused, Community-Based HCV Screening, Linkage-to-Care and Patient Navigation Program.

BACKGROUND: Many of the five million Americans chronically infected with hepatitis C (HCV) are unaware of their infection and are not in care. OBJECTIVE: We implemented and evaluated HCV screening and linkage-to-care interventions in a community setting. DESIGN: We developed a comprehensive, community-based HCV screening and linkage-to-care program in a medically underserved neighborhood with high rates of HCV infection in Philadelphia, Pennsylvania. We provided patient navigation services to enroll uninsured patients in insurance programs, facilitate referrals from primary care physicians and link patients to an HCV infectious disease specialist with intention to treat and cure. PATIENTS: Philadelphia residents were recruited through street outreach. MAIN MEASURES: We measured anti-HCV seroprevalence and diagnosis, linkage and retention in care outcomes for chronically infected patients. KEY RESULTS: We screened 1,301 participants for HCV; anti-HCV seroprevalence was 3.9 % and 2.8% of all patients were chronically infected. Half of chronically infected patients were newly diagnosed; the remaining patients were aware of infection but not in care. We provided confirmatory RNA testing and results, assisted patients with attaining insurance and linked most chronically infected patients to a primary care provider. The biggest barrier to retaining patients in care was obtaining referrals for subspecialty providers; however, we obtained referrals for 64% of chronically infected participants and have retained most in subspecialty HCV care. Several have commenced treatment. CONCLUSIONS: Non-clinical screening programs with patient navigator services are an effective means to diagnose, link, retain and re-engage patients in HCV care. Eliminating referral requirements for subspecialty care might further enhance retention in care for patients chronically infected with HCV.

Nicotine-dependence-varying effects of smoking events on momentary mood changes among adolescents.

INTRODUCTION: Theories of nicotine addiction emphasize the initial role of positive reinforcement in the development of regular smoking behavior, and the role of negative reinforcement at later stages. These theories are tested here by examining the effects of amount smoked per smoking event on smoking-related mood changes, and how nicotine dependence (ND) moderates this effect. The current study examines these questions within a sample of light adolescent smokers drawn from the metropolitan Chicago area (N=151, 55.6% female, mean 17.7years). INSTRUMENTS: Ecological momentary assessment data were collected via handheld computers, and additional variables were drawn from a traditional questionnaire. METHODS: Effects of the amount smoked per event on changes in positive affect (PA) and negative affect (NA) after vs. before smoking were examined, while controlling for subject-averaged amount smoked, age, gender, and day of week. ND-varying effects were examined using varying effect models to elucidate their change across levels of ND. RESULTS: The effect of the amount smoked per event was significantly associated with an increase in PA among adolescents with low-to-moderate levels of ND, and was not significant at high ND. Conversely, the effect of the amount smoked was significantly associated with a decrease in NA only for adolescents with low levels of ND. CONCLUSIONS: These findings support the role of positive reinforcement in early stages of dependent smoking, but do not support the role of negative reinforcement beyond early stages of smoking. Other potential contributing factors to the relationship between smoking behavior and PA/NA change are discussed.

What is the evidence for hardening in the cigarette smoking population? Trends in nicotine dependence in the U.S., 2002-2012.

BACKGROUND: It is unclear whether declines in cigarette smoking in the U.S. have resulted in a hardened population of "hardcore" smokers. We studied changes in nicotine dependence severity from 2002 to 2012, using data from the National Survey on Drug Use and Health. METHODS: We used generalized non-linear factor analysis to examine whether individual Nicotine Dependence Syndrome Scale (NDSS) items functioned differently over time, and whether average NDSS scores changed in a sample of 130,637 current smokers. We also examined trends for individual NDSS sub-scales and whether trends were moderated by tobacco consumption and socio-demographic factors. RESULTS: Consumption levels and dependence severity both declined over the study period. This decline was driven by priority (e.g., avoiding smoke-free locations) and tolerance dimensions of dependence, while drive (e.g., craving and smoking to relieve negative affect) and continuity (e.g., stability) of smoking did not change. Declines for tolerance were greatest among those without serious psychological distress and among middle-aged smokers. Drive and continuity increased among women and low income smokers. CONCLUSIONS: We did not find evidence of hardening at the population level for smokers in the U.S., 2002-2012. However, there is evidence of hardening when considering drive and continuity-related nicotine dependence among women and low-income smokers, suggesting these sub-groups are experiencing greater severity of craving, smoking to relieve negative affect, and regularity of smoking despite reduced consumption.

Prevalence and correlates of unhealthy weight control behaviors: findings from the national longitudinal study of adolescent health.

BACKGROUND: A recent study examined the prevalence, clinical correlates, age trends, and stability of unhealthy weight control behaviors (UWCB; purging and diet pill use) in a nationally representative sample of Norwegian boys and girls. The purpose of this study was to provide similar, comparative analyses for a nationally representative sample of American youth. METHODS: Data were extracted from the restricted use data files of survey Waves I, II, and III of the National Longitudinal Study of Adolescent Health (Add Health), selecting all participants who at Wave I had provided information on age, sex, and UWCB. Using UWCB information, three groups were created (purging, diet pill use, and no recent UWCB "controls") and compared on indicators of adverse health or mental health. RESULTS: Girls consistently were more likely than boys to report UWCB. UWCB were significantly associated with higher body mass index, self-perception of being overweight, low self-esteem, depression, and delinquency. Prevalence estimates for purging remained relatively constant across the three survey waves; in contrast, diet pill use was especially common at Wave III. CONCLUSIONS: Age trends, gender differences, and clinical correlates of change in the likelihood of UWCB between Waves I-III were all identified in analyses comparing purging and diet pill use in American adolescents. Females and older adolescents were specifically more likely to engage in pill use than purging, and individuals with increased weight dissatisfaction, a history of delinquent behaviors, more depression symptoms, or lower self-esteem were more likely to engage in an unhealthy weight control behavior over time. While the Norwegian study found that prevalence of purging was lower among young adult participants, our results suggested that there were no significant differences in prevalence between age groups.

Exploring alternate processes contributing to the association between maternal smoking and the smoking behavior among young adult offspring.

INTRODUCTION: Maternal smoking during pregnancy (MSP) is a known risk factor for regular smoking in young adulthood and may pose a risk independently of mother's lifetime smoking. The processes through which MSP exerts this influence are unknown but may occur through greater smoking quantity and frequency following initiation early in adolescence or increased sensitivity to nicotine dependence (ND) at low levels of smoking. METHODS: This study used path analysis to investigate adolescent smoking quantity, smoking frequency, and ND as potential simultaneous mediating pathways through which MSP and mother's lifetime smoking (whether she has ever smoked) increase the risk of smoking in young adulthood among experimenters (at baseline, <100 cigarettes/lifetime) and current smokers (>100 cigarettes/lifetime). RESULTS: For experimenters, MSP was directly associated with more frequent young adult smoking and was not mediated by adolescent smoking behavior or ND. Independently of MSP, the effect of mother's lifetime smoking was fully mediated through frequent smoking and was heightened ND during adolescence. Controlling for MSP eliminated a previously observed direct association between mother's lifetime smoking and future smoking among experimenters. For current smokers, only prior smoking behavior was associated with future smoking frequency. CONCLUSIONS: These results seem to rule out sensitivity to ND and increased smoking behavior as contributing pathways of MSP. Further, the impact of MSP on young adult smoking extends beyond that of having an ever-smoking mother. Future work should test other possible mediators; for example, MSP-related epigenetic changes or gene variants influencing the brain's nicotine response.

Time-varying effects of smoking quantity and nicotine dependence on adolescent smoking regularity.

BACKGROUND: Little is known about time-varying effects of smoking quantity and nicotine dependence on the regularity of adolescent smoking behavior. METHODS: The sample was drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns Study which followed adolescent smokers over 5 assessment waves spanning 48 months. Participants included former experimenters (smoked <100 cigarettes/lifetime but did not smoke in past 90 days), recent experimenters (smoked <100 cigarettes/lifetime and smoked in past 90 days), and current smokers (smoked >100 cigarettes/lifetime and smoked in past 30 days). Mixed-effects regression models were run to examine the time-varying effects of smoking quantity and nicotine dependence on regularity of smoking behavior, as measured by number of days smoked. RESULTS: Smoking quantity and nicotine dependence were each found to be significantly associated with regularity of adolescent smoking and the size of each effect exhibited significant variation over time. The effect of smoking quantity decreased across time for each smoking group, while the effect of nicotine dependence increased across time for former and recent experimenters. By the 48-month follow-up, the effects of smoking quantity and nicotine dependence had each stabilized across groups. CONCLUSIONS: This study reveals that smoking quantity and nicotine dependence are not static risk factors for the development of more regular smoking patterns. At low levels of smoking when nicotine dependence symptoms are less common, smoking quantity is a stronger predictor of increased regularity of smoking, while for more experienced smokers, nicotine dependence predicts further increases in regularity.

An integrated data analysis approach to investigating measurement equivalence of DSM nicotine dependence symptoms.

INTRODUCTION: Research identifying nicotine dependence (ND) symptoms most appropriate for measurement of adolescent ND and invariant across the range of smoking exposure is hampered by limited sample size and variability of smoking behavior within independent studies. Integrative data analysis, the process of pooling and analyzing data from multiple studies, produces larger and more heterogeneous samples with which to evaluate measurement equivalence across the full continuum of smoking quantity and frequency. METHODS: Data from two studies were pooled to obtain a large sample of adolescent and young adult smokers with considerable variability in smoking. We used moderated nonlinear factor analysis, which produces study equivalent ND scores, to simultaneously evaluate whether 14 DSM ND symptoms had equivalent psychometric properties (1) at different levels of smoking frequency and (2) across a continuous range of smoking quantity, after accounting for study differences. RESULTS: Nine of 14 symptoms were equivalent across levels of smoking frequency and quantity in probability of endorsement at different levels of ND and in ability to discriminate between levels of ND severity. A more precise ND factor score accounted for study and smoking related differences in symptom psychometric properties. CONCLUSIONS: DSM-IV symptoms may be used to reliably assess ND in young populations across a wide range of smoking quantity and frequency and within both nationally representative and geographically restricted samples with different study designs. Symptoms shared across studies produced an equivalently scaled ND factor score, demonstrating that integrating data for the purpose of studying ND in young smokers is viable.

Test-retest reliability of the eating disorder examination-questionnaire (EDE-Q) in a college sample.

BACKGROUND: The Eating Disorder Examination-Questionnaire (EDE-Q), a widely used self-report instrument, is often used for measuring change in eating disorder symptoms over the course of treatment. However, limited data exist about test-retest reliability, particularly for men. The current study evaluated EDE-Q 7-day test-retest reliability in male (n = 47) and female (n = 44) undergraduate students together and separately by gender. RESULTS: Internal consistency was consistently higher for women and at Time 2, but remained acceptable for both men and women at both time points. Cronbach's α ranged from .75 (Restraint at Time 1) to .93 (Shape Concern at Time 2) for women and from .73 (Eating Concern at Time 2) to .89 (Shape Concern at Time 2) for men. With the exception of some of the eating disorder behaviors, test re-test reliability was fairly strong for both men and women. Shape Concern and the global EDE-Q score were highest for both men and women (Spearman's rho > 0.89 with the exception of Shape Concern for women for which Spearman's rho = .86). Test re-test reliability was lower for the eating disorder behavior measures, particularly for men, for whom Kendall's tau-b for frequency and phi for occurrence was less than 0.70 for all but objective bulimic episodes. CONCLUSIONS: Results were consistent with past research for women, indicating strong test re-test reliability in attitudinal features of eating disorders, but lower test re-test reliability in behavioral features. Internal consistency and test re-test reliability was good for the attitudinal features of eating disorder in men, but tended to be lower for men compared to women. The EDE-Q appears to be a reliable instrument for assessing eating disorder attitudes in both male and female undergraduate students, but is less reliable for assessing ED behaviors, particularly in men.

Adolescent nicotine dependence symptom profiles and risk for future daily smoking.

Recent research on adolescent smokers suggests that there are important differences in the types of nicotine dependence (ND) symptoms that emerge and different patterns of ND symptoms. The purpose of this study was to use data from the longitudinal Social and Emotional Contexts of Adolescent Smoking Patterns Study to identify latent subgroups of adolescent experimental and nondaily smokers varying in number and types of endorsed ND symptoms. Profiles were identified using baseline level of smoking, individual patterns of ND symptoms and other ND risk factors. Discrete time survival analysis was used to examine profile differences in probability of becoming daily smokers 48 months later. Four distinct subgroups of smokers with different patterns of smoking behavior, ND symptoms, and alcohol and other substance use emerged. Heavier smoking adolescents with high symptom endorsement, particularly the need to smoke in the morning, were most likely to become daily smokers 48 months later. A subgroup of social smokers had high smoking exposure and symptom endorsement (except need to smoke in the morning), and high levels of other substance use. Despite lower rates of smoking frequency and quantity compared to the heavier smoking class, 36% of these adolescents smoked daily by 48 months, with a steeper decline in survival rates compared to other lighter smoking classes. Morning smoking symptoms and symptoms prioritizing smoking (i.e., choosing to spend money on cigarettes instead of lunch or smoking when ill or where smoking is forbidden) might quickly identify adolescent non-daily smokers with more severe dependence and higher risk for daily smoking. A focus on skills for avoiding social situations involving use of alcohol and other drugs and reducing peer smoking influences may be an important focus for reducing smoking and other substance use among social smokers.