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Concept: Multinomial logit


BACKGROUND: Physical and psychological problems after childbirth are common, and may have a significant negative and long-term impact on women’s wellbeing and daily functioning. The method of birth may be a particularly important factor influencing women’s health and wellbeing following birth, however, population-wide evidence is limited. This study uses data from 5,332 women who responded to a national survey of women’s experiences of maternity care in England. We examined women’s postnatal wellbeing in the first three months after birth, and whether these varied by mode of birth. METHODS: This is a secondary analysis of survey data using a random sample of women selected from birth registration. We used multinomial logistic regression models to examine the association between women’s self-reported psychological symptoms, health problems and mode of birth. RESULTS: Women who had forceps-assisted vaginal births and unplanned caesarean section births reported the poorest health and wellbeing, while those of women who had unassisted vaginal births and planned caesarean section births were less affected by the birth process. Most women’s physical and emotional health appeared to improve with time, however, those who had a forceps-assisted vaginal birth were more likely to report ongoing posttraumatic-type symptoms several months after the birth. CONCLUSIONS: Mode of birth was associated with differences in outcomes at three months. By comparison to women who had unassisted vaginal births, the risk of reduced postnatal health and wellbeing was higher amongst the women who had forceps-assisted vaginal births but not amongst women who had ventouse-assisted vaginal births. This would suggest that it is important to differentiate the different types of instrumental birth in outcome studies. Of concern was the higher rate of posttraumatic-type symptoms among women who had forceps-assisted vaginal births relative to the other modes of birth. Women who have forceps-assisted births should be monitored carefully by health professionals in the postnatal period, and in the months after childbirth, when they could be offered the opportunity to discuss their labour and birth.

Concepts: Regression analysis, Logistic regression, Childbirth, Obstetrics, Multinomial logit, Vagina, Caesarean section, Unassisted childbirth


To better understand the association of alcohol intake with cognitively healthy longevity (CHL), we explored the association between amount and frequency of alcohol intake and CHL among 1,344 older community-dwelling adults. Alcohol intake was assessed by questionnaire in 1984-1987. Cognitive function was assessed in approximate four-year intervals between 1988 and 2009. Multinomial logistic regression, adjusting for multiple lifestyle and health factors, was used to examine the association between alcohol consumption and CHL (living to age 85 without cognitive impairment), survival to age 85 with cognitive impairment (MMSE score >1.5 standard deviations below expectation for age, sex, and education), or death before age 85. Most participants (88%) reported some current alcohol intake; 49% reported a moderate amount of alcohol intake, and 48% reported drinking near-daily. Relative to nondrinkers, moderate and heavy drinkers (up to 3 drinks/day for women and for men 65 years and older, up to 4 drinks/day for men under 65 years) had significantly higher adjusted odds of survival to age 85 without cognitive impairment (p's < 0.05). Near-daily drinkers had 2-3 fold higher adjusted odds of CHL versus living to at least age 85 with cognitive impairment (odds ratio (OR) = 2.06; 95% confidence interval (CI): 1.21, 3.49) or death before 85 (OR = 3.24; 95% CI: 1.92, 5.46). Although excessive drinking has negative health consequences, these results suggest that regular, moderate drinking may play a role in cognitively healthy longevity.

Concepts: Logit, Alcohol, Cognitive psychology, Alcoholism, Cognition, Multinomial logit, Wine, Drinking culture


Koala populations are in catastrophic decline in certain eastern Australian regions. Spanning from 1997-2013, a database derived from wildlife hospitals in southeast Queensland with N = 20,250 entries was classified by causes of morbidity and mortality. A total of 11 aetiologies were identified, with chlamydiosis, trauma, and wasting being most common. The clinical diagnosis at submission varied significantly over the observation period. Combinations of aetiologies were observed in 39% of koalas submitted, with chlamydiosis frequently co-occurring. Urogenital (cystitis 26.8%, bursitis 13.5%) and ocular (conjunctivitis 17.2%) chlamydiosis were the most frequently diagnosed representations of the infection. Approximately 26% of submissions comprised koalas involved in vehicle accidents that were otherwise healthy. Age and sex of the koala as well as season and submission period were compared for the case outcomes of ‘dead on arrival’, ‘euthanized’, or ‘released’ for the four most common clinical diagnoses using multinomial logistic regression models. Exploratory space-time permutation scans were performed and overlapping space-time clusters for chlamydiosis, motor vehicle traumas and wasting unveiled high risk areas for koala disease and injury. Our results suggest that these aetiologies are acting jointly as multifactorial determinants for the continuing decline of koalas.

Concepts: Regression analysis, Logistic regression, Death, Australia, Multinomial logit, Queensland, Koala, South East Queensland


BACKGROUND: Generic alendronate was approved in the United States on February 6, 2008. Medicare beneficiaries might pay for generic alendronate out-of-pocket without having claims submitted, resulting in misclassification of generic alendronate use in Medicare data. OBJECTIVES: To estimate the completeness of generic alendronate use in 2008 Medicare Part D data; to identify factors associated with staying on branded alendronate versus switching to a generic product. METHODS: We identified Medicare beneficiaries highly adherent (medication possession ratio ≥80%) with branded alendronate during 1/1/06-2/6/07 (“2007 cohort”) and during 1/1/07-2/6/08 (“2008 cohort”). The outcome was medication status at the end of follow-up (12/31/2007 or 12/31/2008), classified as continued branded alendronate, switched to generic alendronate, switched to another bisphosphonate or presumed discontinued bisphosphonate therapy. Cox regression estimated the hazard ratio (HR) for discontinuation in 2008 compared to 2007. Multinomial logistic regression identified factors associated with medication status for the 2008 cohort. RESULTS: Among 15 310 subjects using branded alendronate in the 2008 cohort, 81% switched to generic alendronate. The proportion presumably discontinuing bisphosphonate therapy was 8.9% in 2008 compared to 7.7% in the 2007 cohort (adjusted HR, 1.15; 95% confidence interval, 1.05, 1.26). Factors associated with staying on branded alendronate in 2008 were higher income, eligibility for a low income subsidy and use of Fosamax® plus vitamin D. CONCLUSION: Evaluation of Medicare prescription drug data suggests that the amount of missing claims for generic alendronate in 2008 was not substantial, and misclassification of exposure in studies examining alendronate use post-generic product availability should be minimal. Copyright © 2012 John Wiley & Sons, Ltd.

Concepts: Pharmacology, Regression analysis, Prescription drug, Medicare, Statistics, Multinomial logit, Medicare Part D, Medicare Prescription Drug, Improvement, and Modernization Act


BACKGROUND: This study was designed to assess the relationship between work-related combined physical and psychosocial factors and elbow disorders (lateral epicondylitis and non-specific disorders without lateral epicondylitis) in the working population. METHODS: A total of 3,710 workers (58% men) in a French region in 2002-2005 participated in physical examinations by occupational health physicians and assessed their personal factors and work exposure by self-administered questionnaire. Statistical associations between elbow disorders and risks factors were analyzed using multinomial logistic regression. RESULTS: A total of 389 (10.5%) workers had elbow pain without lateral epicondylitis and 90 (2.4%) workers had lateral epicondylitis. Age, body mass index (>25), and low social support (only for men) were significant risks factors. Hard perceived physical exertion combined with elbow flexion/extension (>2 hr/day) and wrist bending (>2 hr/day) was a strong significant risk factor for elbow pain and epicondylitis: among men, adjusted Odds Ratio (ORa) = 2.6 (1.9-3.7) and ORa = 5.6 (2.8-11.3), respectively; among women, ORa = 1.4 (0.9-2.2) and ORa = 2.9 (1.3-6.5). CONCLUSIONS: This study emphasizes the strength of the associations between combined physical exertion and elbow movements and lateral epicondylitis. Certain observed differences in associations with lateral epicondylitis and elbow pain only indicate the need for additional longitudinal studies on different stages of elbow disorders and known risk factors. Am. J. Ind. Med. © 2012 Wiley Periodicals, Inc.

Concepts: Regression analysis, Logit, Epidemiology, Medical statistics, Risk, Body mass index, Multinomial logit, Risk factor


Although emotional congruence with children (ECWC) is a risk factor for sexual offending against children, its conceptual validity has hardly been researched. This study aims to explore the construct of ECWC by evaluating the factor structure of the Child Identification Scale (CIS-R) and its relation to facets of sexual preference and child sexual abuse behaviors. It was hypothesized that the measure comprises consistent subscales that are differently associated with aspects of sexual preference and sexual offending against children. CIS-R data of a sample of 217 adult male pedophiles from the community were used for an exploratory principal component analysis (PCA). Group comparisons and a multinomial logistic regression analysis were conducted after including a non-pedophilic control group of 22 adult men. PCA revealed a three-factor solution for the CIS-R accounting for 30% of variance. Group comparisons found differences in overall scores and the factor labeled “Attachment to Children” between subgroups of sexual age and gender preference, but not between contact, online, and non-offenders. The regression analysis showed a pedophile sexual preference and the interaction between a hebephile sexual age preference and the factor “Attachment to Children” being associated with past offending behavior. The results indicate a wish to attach to children as core feature of the CIS-R measure assessing ECWC. It is discussed whether this is an inherent feature of pedophilia or rather an independent aspect being differently distinct in pedophiles.

Concepts: Regression analysis, Logistic regression, Principal component analysis, Child sexual abuse, Child pornography, Multinomial logit, Pedophilia, Hebephilia


The purpose of this study was to examine factors hindering the use of mouthguards and the incidence of orofacial injury among young male rugby players. 69 high school rugby players (Group 1) and 431 medical student rugby players (Group 2) participated in this study. Participants in Group 1 used custom-made mouthguards fabricated according to a standardized method, whereas participants in Group 2 used custom-made or over-the-counter mouthguards of their choice. The factors associated with orofacial injury were assessed by logistic regression analysis, while factors hindering mouthguard use were assessed by multinomial logistic regression analysis. All data were obtained from a questionnaire developed by the Japanese Academy of Sports Dentistry. We found that breathing problems were the main factor contributing to the reduced frequency of mouthguard use. In both groups, a significant negative association was observed between the frequency of mouthguard use and the risk of orofacial injury. The group using standardized custom-made mouthguards reported fewer complaints about breathing problems and a higher frequency of mouthguard use. The results of this study suggest that increasing the frequency of mouthguard use would reduce the risk of orofacial injury among young male rugby players. We also conclude that users of custom-made mouthguards complain less frequently of breathing difficulties.

Concepts: Regression analysis, Logistic regression, Statistics, Econometrics, Probit model, Multinomial logit, Francis Galton, Rugby union equipment


Possible links of cyberbullying with suicide and psychological problems have recently received considerable attention. Suicide-related behaviors have also been linked with viewing of associated web content. Studies on traditional bullying indicate that the roles of bullying involvement (bullies, victims, and bully-victims) matter in terms of associations with specific suicide-related behaviors and psychological problems. Yet, related research in the area of cyberbullying is lacking. The current study investigates the association of cyberbullying roles with viewing of specific suicide-related web content and psychological problems. Data from N = 19,406 (50 percent girls) 11-16-year-olds (M = 13.54, SD = 1.68) of a representative sample of Internet-using children in Europe were analyzed. Self-reports were obtained for cyberbullying role, viewing of web content related to self-harm, and suicide, as well as the emotional, peer, and conduct problem subscales of the Strengths and Difficulties Questionnaire (SDQ). Multinomial logistic regression analyses revealed that compared with those not involved in cyberbullying, viewing of web content related to suicide was higher for cybervictims and cyberbully-victims, but not for cyberbullies. Viewing of web content related to self-harm was higher for all cyberbullying roles, especially for cyberbully-victims. Rates of emotional problems were higher among cybervictims and cyberbully-victims, rates of peer problems were higher for cybervictims, and rates of conduct problems were higher for all cyberbullying roles. Moreover, the links between cyberbullying role and viewing of suicide-related web content were independent of psychological problems. The results can be useful to more precisely target efforts toward the specific problems of each cyberbullying role. The outcomes on viewing of web content also indicate an opportunity to enhance the presence of health service providers on Internet platforms.

Concepts: Psychology, Regression analysis, Logistic regression, Sociology, Multinomial logit, Role, Bullying, Web content


Background: The majority of smokers regret ever starting to smoke, yet the vast majority continue to smoke despite the fact that smoking kills nearly 50% of lifetime users. This study examined the relationships between regret and smoker characteristics, quit history, risk perceptions, experiential thinking, and beliefs and intentions at time of smoking initiation. Methods: Data from the 2014 Tobacco Products and Risk Perceptions Survey, a nationally representative survey of United States adults, were analyzed to provide the latest prevalence estimates of regret and potential predictors. Relationships among predictor variables and regret were analyzed using correlations, t-tests, and multinomial logistic regression. Results: The majority of smokers (71.5%) regretted starting to smoke. Being older and non-Hispanic white were significant predictors of regret. Smokers having a high intention to quit, having made quit attempts in the past year, worrying about getting lung cancer, believing smoking every day can be risky for your health, perceiving a risk of being diagnosed with lung cancer during one’s lifetime, and considering themselves addicted to cigarettes were significant predictors of regret for smoking initiation. Conclusions: This study provides updated prevalence data on regret using a national sample, and confirms that regret is associated with perceived risk. The findings from this study can be used to inform smoking intervention programs and support the inclusion of smoker regret in cost-benefit analyses of the economic impact of tobacco regulations.

Concepts: Cancer, Risk, Tobacco, Tobacco smoking, Nicotine, Perception, Mind, Multinomial logit


Social networking sites (SNSs) have gained substantial popularity among youth in recent years. However, the relationship between the use of these Web-based platforms and mental health problems in children and adolescents is unclear. This study investigated the association between time spent on SNSs and unmet need for mental health support, poor self-rated mental health, and reports of psychological distress and suicidal ideation in a representative sample of middle and high school children in Ottawa, Canada. Data for this study were based on 753 students (55% female; Mage=14.1 years) in grades 7-12 derived from the 2013 Ontario Student Drug Use and Health Survey. Multinomial logistic regression was used to examine the associations between mental health variables and time spent using SNSs. Overall, 25.2% of students reported using SNSs for more than 2 hours every day, 54.3% reported using SNSs for 2 hours or less every day, and 20.5% reported infrequent or no use of SNSs. Students who reported unmet need for mental health support were more likely to report using SNSs for more than 2 hours every day than those with no identified unmet need for mental health support. Daily SNS use of more than 2 hours was also independently associated with poor self-rating of mental health and experiences of high levels of psychological distress and suicidal ideation. The findings suggest that students with poor mental health may be greater users of SNSs. These results indicate an opportunity to enhance the presence of health service providers on SNSs in order to provide support to youth.

Concepts: Health care, Psychology, Regression analysis, Logistic regression, High school, Mental disorder, Multinomial logit, Social network service