Reducing musculoskeletal disorders in iron ore mine operators: A fuzzy-based intervention approach.

BACKGROUND: This study focuses on evaluating the exposure to whole-body vibration (WBV) and association of musculoskeletal disorders (MSDs) with various risk factors among dumper operators in the mining industry. Despite the issue's significance, prior research has been limited. OBJECTIVE: The study introduces a novel fuzzy-based approach for identifying, selecting, and prioritizing safety measures to mitigate MSD risks. METHODS: Data collection comprised face-to-face interviews, anthropometric measurements, Rapid Upper Limb Assessment (RULA) scoring for posture assessment, and the Nordic Musculoskeletal questionnaire for assessment of MSD prevalence. Multiple linear and logistic regression models were used to analyse the contributing risk factors to MSDs and WBV exposure. These risk factors formed the basis for a practical approach to select appropriate safety measures based on fuzzy based aggregation method of expert's judgment aimed at mitigating the risk of MSDs. RESULTS: The results revealed that the risk factors such as poor work posture, WBV exposure and poor seat design were significantly associated with neck (adjusted odds ratio aOR = 4.81), upper limb and shoulder (aOR = 3.28), upper back (aOR = 5.09), and lower back pain (aOR = 3.67) at p < 0.05. Using these factors to formulate safety measures to reduce MSD risk, the minimization of sharp turns and abrupt changes in elevation in designing the haul roads, scheduled maintenance practices, and ergonomic seat design were found as important safety measures in this study. CONCLUSION: Our unique methodological approach in occupational health research could be highly beneficial for tailoring safety measures at the unit level with minimal effort.

Untreated Allergy Among Middle School Students: Associations with Socioeconomic Adversities and Academic, Behavior, and Health Difficulties.

BACKGROUND: Many adolescents with allergy do not receive physician treatment (allergyuntreated). We explored its association with socioeconomic adversities and academic-behavior-health difficulties, which remain unaddressed. METHODS: This cross-sectional school-based-population study compared the above factors of middle-school adolescents with allergyuntreated and those with treated allergy (allergytreated) (mean age = 13.5 ± 1.2) from north-eastern France. Participants completed a questionnaire collecting socioeconomic adversities (nonintact family, low parents' education, insufficient family income, poor social support, suffered verbal/physical violence, and sexual abuse), low academic performance, excessive screen time, substance use, sleep difficulty, poor physical health, depressive symptoms, suicide attempt, poor quality of life, and allergytreated/allergyuntreated. RESULTS: Logistic regression models showed that allergyuntreated was associated with all the factors considered (sex-age-class-level-adjusted odds ratio (saclOR) reaching 3.94, p < .001) and the risk score (number of main criteria: suffered sexual abuse, excessive screen time, poor quality of life, cannabis use, low parents' education, and poor social support): saclOR 4.75, 9.23, 15.64, and 31.73 (p < .001) for risk scores 1, 2, 3, and ≥4, versus risk score = 0 (pseudo-R2 = 11.1%). CONCLUSIONS: Socioeconomic adversities and academic-behavior-health difficulties may be used to detect adolescents with allergyuntreated for care.

Substance Use Among Middle School Adolescents: Association with Family Members' and Peers' Substance Use and the Mediating Role of School and Mental Difficulties.

OBJECTIVE: We assessed the associations of substance (alcohol, tobacco, cannabis, and other illicit drugs) use of adolescents with that of their family members (father, mother, step-parent, brothers/sisters, and grandparents) and peers, and the mediating role of school and mental difficulties (SMDs) which remained insufficiently addressed. METHODS: This cross-sectional population-based study included 1,559 middle-school adolescents in France (mean age = 13.5 ± 1.3, 778 boys, 781 girls). They completed a questionnaire including socioeconomic features (nationality, family structure and parents' education, occupation, and income), substance use, cumulative number of substance use of family members (father, mother, step-parent, brothers/sisters, and grandparents) and peers (noted familySUcn and peerSUcn), SMDs (grade repetition, suffered physical/verbal violence, sexual abuse, lack of family/peer support, depressive symptoms, suicide attempt, and age at onset). Data were analyzed using logistic regression models and Kaplan-Meier estimates. RESULTS: Most adolescents had familySUcn 1-2, 3-5, and ≥ 6 (39.1%, 23.0%, and 4.5%, respectively) and peerSUcn 1-2 and ≥ 3 (36.1% and 13.0%, respectively). Strong dose-effect associations were found between all substance use and familySUcn and peerSUcn (odds ratio adjusted for sex, age, and socioeconomic features reaching 13.44 and 9.90, respectively, most with p < .001). SMDs explained more the associations of all substance use with familySUcn than with peerSUcn (contributions reaching 69% and 34%, respectively). The proportion of subjects without each substance use decreased with age more quickly among the adolescents with higher familySUcn or peerSUcn. CONCLUSIONS: Early prevention reducing familySUcn, peerSUcn and SMDs among adolescents and their families may reduce efficiently initiation and regular use of substances during adolescents' life course.

Many adolescents had a high cumulative number of family members' and peers' substance (alcohol, tobacco, cannabis, or other illicit drugs) use (familySUcn and peerSUcn)Strong dose­effect links of substance use with familySUcn and peerSUcn (odds ratio up to 13)School and mental difficulties explained up to 69% of the link of substance use with familySUcn and up to 34% of that of substance use with peerSUcnThe proportion of subjects without each substance use decreased with age more quickly among the adolescents with higher familySUcn/peerSUcn than among the othersOur results may help implementing prevention to reduce substance use.

Associations of Postural Activities and Knowledge for Voice with Breathing Issues and Voice-Physical-Disorders Among Lyric Singers.

OBJECTIVES/HYPOTHESIS: The purpose of this research was to study the associations of postural activities and knowledge of the voice of opera singers, recognized in the literature for the specificity of their posture. Additionally, the link between vocal pathologies and body pains on one hand, and posture control on the other hand was investigated. METHODS: A questionnaire including 90 questions was distributed to singers in France and overseas during 6 months. Ninety-eight opera singers participated in the survey. Data were analyzed using Excel and Stata software. RESULTS: The results showed that the singers who paid more attention to posture, postural work while singing, had knowledge of anatomy and postural role in singing voice, healthy lifestyle, and good body habits, had less vocal discomfort and pathologies, a better vocal preservation, and used more costo-abdominal breathing. On the other hand, knowledge of postural role and postural work was linked with pain and vocal fatigue. Furthermore, a preventive need was revealed concerning the providing of knowledge and skills to singers, but also to singing teachers, speech therapists, and stage workers. CONCLUSION: Our study shows that benefits were found in the voice quality of opera singers with anatomical and postural knowledge and who work on posture as part of their vocal work compared to others. Postural work and knowledge increase attention to body pain and vocal fatigue. These results can inform health care providers, opera singers, and their teachers and performers of the benefits of posture on operatic voice quality. Accordingly, this study sparks new ideas for postural work and therapy in lyric voice.

Development of an intervention program to reduce whole-body vibration exposure based on occupational and individual determinants among dumper operators.

Objectives. Studies related to a systematic approach for intervention design to reduce whole-body vibration (WBV) exposure are scarce. This study presents a systematic approach to identifying, selecting and prioritizing safety interventions to fulfill that research gap. Methods. A total of 130 vibration readings for dumper operators were taken from two surface iron ore mines to identify significant determinants of WBV exposure. Initially, age, weight, seat design, awkward posture, machine's age, load tonnage, dumper speed and haul road condition were hypothesized as determinants. Data were collected through standardized questionnaires and field-based observation. A multivariate statistical approach was applied for the practical use of the intervention program. Results. As some of the hypothesized factors were correlated, exploratory factor analysis (EFA) followed by multiple linear regression (MLR) was used to investigate their association with WBV exposure. As per EFA results, hypothesized factors were clubbed under individual, ergonomics and occupational factors. Occupational and ergonomics factors were found to be significantly associated with WBV exposure through MLR and used to form safety interventions to reduce WBV exposure. Conclusions. Our methodological approach is original in the occupational health research area and can be helpful to tailor the safety interventions for the unit level with minimum effort.

A practical framework to develop and prioritize safety interventions to improve underground coal miners' safety performance.

BACKGROUND: Improvement of workers' safety performance is an integral and essential part of safety management. Relevant safety interventions to improve workers' safety performance are generally difficult to establish when there is a wide range of occupational hazards and at-risk individuals' features. OBJECTIVE: This study aimed at formulating a practical approach to develop and prioritize potential safety interventions based on occupational and individual risk factors perceived by workers to promote workers' safety performance. METHODS: A simple framework developed to identify and prioritize the suitable safety interventions. This framework made use of data collected using standardized and validated questionnaire and domain experts' opinions. Pearson correlation coefficients, exploratory factor analysis, and multiple linear regression were used to identify significant risk factors associated with workers' safety performance. Data were collected by interviewing 202 coal mine workers with occupational injuries, and their immediate supervisors from three mines. RESULTS: Safety performance was associated with the occupational factor-domain (poor working condition, poor safety environment, poor job satisfaction, and high job stress) only (regression coefficient = 2.14, p < 0.01). The following interventions were identified and prioritized to promote workers' safety performance: provide fair compensation to workers, job-specific and safety training, promotion policy, achievable targets, relevant perks/benefits, safety training awareness, workplace lighting, ventilation network, sensitize the management, associate safety performance to promotion, and develop team spirit. CONCLUSION: Our approach helps to identify and prioritize the most relevant interventions to promote safety at work when there are multiple risk factors.

Associations between excessive screen time and school and out-of-school injuries among adolescents: A population-based study.

Most adolescents spend excessive screen time (with television viewing, computer/console gaming, discussion forums/chatting online, internet surfing, doing homework, and electronic mails) which may impact the occurring of various types of school and out-of-school injuries. We assessed their associations and potential confounding factors among 1559 middle-school students from north-eastern France (mean age=13.5 ± 1.3). Participants completed a questionnaire including socioeconomic features, daily screen time for various screen-based activities (coded 1=<2, 2 = 2-4, 3=≥5 h; daily-total-screen time level (TDST) was defined as their sum, categorized into <7/7-11/≥12), various injury types during the school-year, behavior and health difficulties (BHDs; alcohol/tobacco/cannabis/other illicit drugs use, suffered physical/verbal violence, sexual abuse, poor family-peer support, sleep difficulty, depressive symptoms, suicide attempt, and time at onset). Most subjects had TDST≥7 (82.3 %). There were dose-effect associations of TDST with school-physical/sports training, school-free-time, out-of-school-sports, and single/repeated injuries (sex-age-adjusted odds ratio reaching 4.45). BHDs explained up to 39 % of these associations. The frequency of subjects without various BHDs decreased with age since age 10 more quickly among the participants with both TDST≥7 and injury than among the others. Our findings may inform health care providers, parents, schools, and public policy that reducing elevated screen time is efficient to prevent injuries and BHDs among adolescents.

Associations between School-Behavior-Health Difficulties and Subsequent Injuries among Younger Adolescents: A Population-based Study.

Objective: School-behavior-health difficulties (SBHDs) may alter physical/mental capabilities and consequently increase injury risk during daily activities. This study assessed the associations of potential SBHDs and their cumulative number (SBHDcn) with various injury types among younger adolescents. Methods: The study population included 1,559 middle-school adolescents in France (10-18 years, 98% under 16,778 boys and 781 girls). They completed a questionnaire at school-year end collecting socioeconomic features (nationality, family structure, parents' education/occupation/income), school/out-of-school injuries during the school-year (dependent variables), and SBHDs starting before the school-year (low academic performance, alcohol/tobacco/cannabis/other-illicit-drugs use, physical/verbal violence, sexual abuse, perpetrated violence, poor social support, poor general health status, sleep difficulty, depressive symptoms, and suicide attempt). Data were analyzed using logistic regression models and Kaplan-Meier estimates. Results: Injuries were frequent during school-physical/sports-training (10.9%), other-school-training (4.7%), school-free-time (7.4%), out-of-school-sports-activity (16.5%), and traffic (2.2%). Single injury (one injury all injury types combined) and ≥2 injury types affected 23.3 and 7.9% of subjects, respectively. The proportion of adolescents without SBHDs decreased with age more quickly among those with each injury type than among those without injury. Various SBHDs were associated with most injury types, single injury, and ≥2 injury types (sex-age-adjusted odds/relative-risk ratios reaching 11, p < .001). A dose-effect association was found between SBHDcn 1-2/3-5/≥6 and both single injury and ≥2 injury types (sex-age adjusted relative risk ratios reaching 12.66, p < .001, vs. SBHDcn = 0). Socioeconomic features had a moderate confounding role in these associations. Conclusions: SBHDs strongly predict injuries among adolescents. Our findings may inform healthcare providers about their prominent role in detecting/reducing SBHDs and injuries.

Association of School Health Relationship Difficulties with Lack of Regular Physical Activity in Younger Adolescents: A Population Based Study.

Objective: Lack of regular physical activity (LPA) and the number of days/week with physical activity >60 minutes/day (Ndw) may be associated with school-health-relational difficulties (SHRDs) during the life-course. This study assessed their associations and the confounding role of socioeconomic features (nationality, family structure, parents' education/occupation/income) among younger adolescents. Methods: This cross-sectional population-based study included 1,559 middle-school adolescents from north-eastern France (10-18 years, 98% under 16 years, 778 boys and 781 girls). They completed over one-hour teaching period a questionnaire collecting last-12-month LPA and last-7-day Ndw (dependent variables), and risk factors including socioeconomic features, SHRDs (previous grade repetitions, last-12-month poor general health status/physical health/psychological health/social-relationships, depressive symptoms (and age at onset and duration from onset); cumulated number noted SHRDcn). Data were analyzed using logistic/linear regression models. Results: LPA was common (32.5%) and associated with all SHRDs (sex-age-adjusted odds ratio saOR reaching 1.99, p < .001) and depressive-symptoms duration (saOR 1.63 (p < .05) and 2.11 (p < .001) for 1-2 and ≥3 years, respectively, vs. no depressive symptoms). A dose-effect association was found between SHRDcn and LPA (24.0, 33.7, 45.6, and 53.5%; saOR 1.59, 2.58, and 3.43; for SHRDcn 1-2, 3-4, and ≥5 respectively, vs. SHRDcn = 0, p < .001). Ndw was similarly associated with all SHRDs and SHRDcn (sex-age-adjusted regression coefficient reaching -1.10 day/week, p < .001). These results were robust when controlling for socioeconomic features (18%

• Lack of physical activity (LPA) is strongly associated with school-health-relational difficulties (SHRDs) affecting most adolescents.• There are dose-effect associations between cumulative number of SHRDs and both LPA and number of days/week with physical activity >60 min/day (Ndw).• These links are robust when controlling for socioeconomic features which have a strong confounding role.• The risk of LPA and reduced Ndw increase with the duration of depressive symptoms from their onset.• Prevention to detect/reduce SHRDs may improve physical activity, especially for most at-risk adolescents.

Association between untreated low back pain and injury proneness and confounding role of behavioral-health difficulties among younger adolescents: a population-based study.

PURPOSE: Low back pain (LPB) is mostly left untreated (LBPuntreated) and may increase the injury risk due to associated behavioral-health difficulties (BHDs) among adolescents. This study assessed the association between LBPuntreated (vs. treated LBP (LBPtreated)) and injuries and the mediating role of BHDs among younger adolescents (10-16 years). METHODS: This population-based study compared 328 adolescents with LBPuntreated (mean age = 13.7 ± 1.3) with 291 with LBPtreated (mean age = 13.3 ± 1.2) from north-eastern France. They completed a questionnaire collecting, at school-year end, socioeconomic features, LBPtreated/LBPuntreated, BHDs (alcohol/tobacco use, excessive screen-time, poor social support, poor physical health, depressive symptoms, and pain limiting activities), and injuries during the current school-year. Data were analyzed using multinomial logistic regression models and Kaplan-Meier estimates. RESULTS: The proportion of subjects without alcohol/tobacco use or depressive symptoms decreased with time more quickly since age 10 among the adolescents with LBPuntreated than among those with LBPtreated. Hence, most LBP early started and the subjects with LBPuntreated had a higher risk of single injury (sex-age-class-level-socioeconomic-features-adjusted relative risk ratio RR = 1.63, p < 0.05, vs. LBPtreated) and a much higher risk of ≥ 2 injuries (RR = 2.60, p < 0.001). BHDs played a strong mediating role in the association between LBPuntreated and ≥ 2 injuries (contribution = 48%) but a modest mediating role in that between LBPuntreated and single injury (contribution = 10%) (pseudo R2 = 7.6%). CONCLUSION: LBPuntreated is common and associated with injuries partly due to BHDs (which may alter physical/mental capabilities, risk perception/awareness, and vigilance) among younger adolescents. Our results may inform healthcare providers that they can detect/treat LBP and BHDs to prevent their aggravation and injuries.

Association between screen time and cumulating school, behavior, and mental health difficulties in early adolescents: A population-based study.

Early adolescents may daily spend excessive screen-time (with television viewing, computer/console gaming, discussion forums/chatting online, internet surfing, doing homework, and electronic mails) while its association with cumulating several school-behavior-mental-health difficulties (SBMDs) (poor-academic-performance, being obese, alcohol/tobacco/cannabis/other-illicit-drugs use, suffered violence, sexual abuse, perpetrated violence, poor social support, depressive symptoms, and suicide attempt) is poorly addressed. We investigated this association among 1559 middle-school adolescents from north-eastern France (mean age 13.5 ± 1.3). They completed a questionnaire including socioeconomic features, daily screen-time for various screen-based activities (coded 1=<2/2=2-4/3=≥5 h; daily-total-screen-time level DSAtotal was defined as their sum and categorized into 4 levels: 6-7/8-9/10-12/≥13), various SBMDs and the time of their onset during the life course (their cumulated number SBMDscore was categorized into 5 levels: 0/1/2/3-4/≥5). Logistic regression modeling showed that the DSAtotal was strongly associated with all SBMDs (gender-age-adjusted odds ratio reaching 8.28, p < 0.001) and SBMDscore (gender-age-adjusted relative risk reaching 11.60, p < 0.001, pseudo R2 = 0.039). These associations remained strongly significant when controlling for socioeconomic adversities (contributions 20-38%). The proportion of subjects without each SBMD steadily decreased with age according to DSAtotal levels. These findings help to understand the impacts of high DSAtotal on SBMDs in early adolescents and identify at-risk adolescents for prevention and care.

Association between Whole-Body Vibration exposure and musculoskeletal disorders among dumper operators: A case-control study in Indian iron ore mines.

BACKGROUND: Dumper operators in mines worldwide are subjected to Musculoskeletal Disorders (MSDs) due to whole-body vibration exposure. This study evaluated the working-life-Whole-Body Vibration (WBV)-exposure and their association with various MSDs among dumper operators in mines which remains poorly addressed. METHODS: This case-control study in Indian iron ore mines was conducted to compare randomly selected 65 dumper operators and 65 office workers. Data were collected through face-to-face interviews using the Nordic Musculoskeletal Questionnaire (NMQ) and were analysed using logistic regression models. RESULTS: The study revealed that majority of the dumper operators were exposed to WBV exceeding the ISO-2631 limits. Compared with controls, the dumper operators had a much higher risk of upper back pain (age-overweight-adjusted odds ratio ORao = 5.37, 95% CI = 1.78-16.20), lower back pain (ORao = 2.72, 95% CI = 1.25-5.94), knee and leg pain (ORao = 3.68, 95% CI = 1.22-11.11), and having 2+ MSDs (ORao = 5.05, 95% CI = 1.88-13.51, vs. no MSDs). Working-life-WBV-exposure was higher among dumper operators having upper back pain (mean (SD) = 7.1 (1.91) vs. 5.7 (1.91), p < 0.01) and lower back pain (mean (SD) = 6.63 (2.10) vs. 5.55 (1.71), p < 0.01) compared to those without these MSDs. Older age was associated with higher risk of MSD pains. CONCLUSION: Dumper operators have excess MSDs due to high working-life-WBV-exposure. Their MSDs and working-life-WBV-exposure should be regularly evaluated and reduced.

Associations of job-related hazards and personal factors with occupational injuries at continuous miner worksites in underground coal mines: a matched case-control study in Indian coal mine workers.

A wide range of job-related hazards and personal factors may be associated with injury occurrences at continuous miner worksites but their role has been little documented. To address this issue, a case-control study in India was conducted to compare 135 workers with an injury during the previous 2-yr period and 270 controls without injury during the previous 5-yr period (two controls for each injured worker, matched on age and occupation). Data were collected through face-to-face interviews using standardized questionnaire and analyzed using conditional logistic regression models. We found that the injury occurrences were multifactorial and associated with hand tool-related hazards (adjusted odds ratio/ORa=3.69, p<0.01), working condition-related hazards (ORa=3.11, p<0.01), continuous miner-related hazards (ORa=1.95, p<0.05), and shuttle car-related hazards (ORa=6.95, p<0.001), along with big family size, no-formal education, and presence of disease (adjusted odds ratios varying between 2 to 4). Stratified analyses showed that among the 36-60 yr-old workers, hand tool-related hazards, working condition-related hazards, and shuttle car-related hazards had significant ORa (6.62, 4.38 and 15.65, respectively with p<0.01,) while among the younger workers, only shuttle car-related hazards had significant ORa (4.25, p<0.05). These findings may help to understand the risk patterns of injuries and to implement appropriate prevention strategies.

Association between cumulating substances use and cumulating several school, violence and mental health difficulties in early adolescents.

Multiple substances (alcohol, tobacco, cannabis and other illicit drugs (OID)) have been frequently used in early adolescents maybe due to school, violence and mental-health difficulties. We investigated the associations between substance-use patterns and related difficulties among 1559 middle-school adolescents from north-eastern France (mean age 13.5 ±â€¯1.3). They completed a questionnaire including socioeconomic features, school, violence and mental-health difficulties (school grade repetition, sustained physical/verbal violence, sexual abuse, perpetrated violence, poor social support, depressive symptoms and suicide attempt; cumulated number noted SVMDscore) and the time of their first occurrence during the life course. Data were analyzed using logistic and negative binomial regression models. Alcohol, tobacco, cannabis and OID use affected 35.2, 11.2, 5.6 and 2.8% of the subjects respectively. The risk of using tobacco only, alcohol and tobacco, alcohol plus tobacco and cannabis, or all alcohol, tobacco, cannabis and OID strongly increased with the SVMDscore (socioeconomic features-adjusted odds ratio reaching 85). The risk began in early years in middle schools and then steadily increased, more markedly for elevated SVMDscore. Exposure to several SVMDs may be a transmission vector towards the substance use, starting mostly with alcohol/tobacco, and then shifting to cannabis/OID. These findings help to understand substance-use risk patterns and identify at-risk adolescents.

Association between Suicide Ideation and Attempts and Being an Immigrant among Adolescents, and the Role of Socioeconomic Factors and School, Behavior, and Health-Related Difficulties.

The risk of suicide behaviors in immigrant adolescents varies across countries and remains partly understood. We conducted a study in France to examine immigrant adolescents' likelihood of experiencing suicide ideation in the last 12 months (SI) and lifetime suicide attempts (SA) compared with their native counterparts, and the contribution of socioeconomic factors and school, behavior, and health-related difficulties. Questionnaires were completed by 1559 middle-school adolescents from north-eastern France including various risk factors, SI, SA, and their first occurrence over adolescent's life course (except SI). Data were analyzed using logistic regression models for SI and Cox regression models for SA (retaining only school, behavior, and health-related difficulties that started before SA). Immigrant adolescents had a two-time higher risk of SI and SA than their native counterparts. Using nested models, the excess SI risk was highly explained by socioeconomic factors (27%) and additional school, behavior, and health-related difficulties (24%) but remained significant. The excess SA risk was more highly explained by these issues (40% and 85%, respectively) and became non-significant. These findings demonstrate the risk patterns of SI and SA and the prominent confounding roles of socioeconomic factors and school, behavior, and health-related difficulties. They may be provided to policy makers, schools, carers, and various organizations interested in immigrant, adolescent, and suicide-behavior problems.

Associations between school difficulties and health-related problems and risky behaviours in early adolescence: A cross-sectional study in middle-school adolescents in France.

Health-related problems and risky behaviours (substance use) are frequent in adolescents, may alter their physical and mental capabilities, and may thus generate school absenteeism, low academic performance, and school dropout ideation. This study assessed their associations and the contribution of socioeconomic factors among 1559 middle-school adolescents (mean age 13.5+1.3) from north-eastern France. They completed a questionnaire including socioeconomic characteristics, health-related problems (poor physical health, psychological health, social relationships, and living environment) assessed with the World Health Organization's quality of life measure (score<25th percentile), risky behaviours, school absences during the present school year, last-trimester academic performance, and school dropout ideation. Data were analysed using logistic regression models. School absenteeism was frequent (12.6% of subjects for 8-14 days, and 6.0% for ≥15 days); 8.2% of subjects had low academic performance (average school-mark <10/20) and 3.9% school dropout ideation. All school difficulties were strongly associated with all health-related problems (gender-age-school-level-adjusted odds ratios gasOR between 1.5 and 4.2), and with risky behaviours (gasOR between 1.4 and 14). Socioeconomic factors differently contributed to these associations (contribution reaching 77%). Policy makers, schools, physicians and parents should be more aware of the problems and help adolescents to reduce health-related problems and risky behaviours and to increase resilience.

From cannabis initiation to daily use: educational inequalities in consumption behaviours over three generations in France.

AIMS: The diffusion of cannabis initiation has been accompanied by a reversal in the educational gradient: contrary to older generations, the less educated in recent generations are more likely to initiate than the more educated. We tested whether the educational gradient for the transition from initiation to daily use evolved in the same way. DESIGN/SETTING: A French telephone random survey conducted in 2010 (21 818 respondents aged 15-64 years), asking interviewees about their ages at initiation to daily use, if any. PARTICIPANTS: A total of 6824 cannabis initiators aged 18-64 years at data collection. Three birth cohort groups (generations) were compared: 1946-60 (n = 767), 1961-75 (n = 2632) and 1976-92 (n = 3425) with, respectively, 47, 42 and 45% of women. MEASURES: Risks of transition to daily use from ages 11-34 were compared through time-discrete logistic regressions and educational gradients were quantified through a relative index of inequality (RII). Control variables include age and time-varying variables (ages at tobacco daily use, at first drunkenness and at first other use of an illicit drug in a list of 13 products). FINDINGS: Twenty-four per cent of the initiators reported daily use before age 35, the proportions tripling from the oldest to the youngest generation (from 11.7 to 38.6% in men, from 7.7 to 22.2% in women). Whatever the generation, the less educated initiators more often shifted to daily use than the most educated: from the oldest to the youngest generation, RII = 2.13, 95% confidence interval (CI) = [0.65, 7.02]; 2.19 95% CI = [1.33, 3.63]; and 2.24, 95% CI = [1.60, 3.15] in men; RII = 3.31, 95% CI = [0.75, 14.68]; 3.17, 95% CI = [1.49, 6.76]; and 3.56, 95% CI = [2.07, 6.14] in women, respectively. CONCLUSION: In France, the risk of transition from cannabis initiation to daily use has remained consistently higher among less educated cannabis initiators over three generations (1946-60, 1961-75, 1976-92), in contrast to what is observed for initiation.

The Gateway Hypothesis, Common Liability to Addictions or the Route of Administration Model A Modelling Process Linking the Three Theories.

BACKGROUND: The aim of this study was to describe the transitions between tobacco (T), cannabis (C) and other illicit drugs (OIDs) initiations, to simultaneously explore several substance use theories: gateway theory (GT), common liability model (CLM) and route of administration model (RAM). METHODS: Data from 2 French nationwide surveys conducted in 2005 and 2010 were used (16,421 subjects aged 18-34). Using reported ages at initiations, we reconstituted a retrospective cohort describing all initiation sequences between T, C and OID. Transition probabilities between the substances were computed using a Markov multi-state model that also tested the effect of 2 latent variables (item response theory scores reflecting propensity for early onset and further substance use) on all transitions. RESULTS: T initiation was associated with increased likelihood of subsequent C initiation, but the reverse relationship was also observed. While the most likely initiation sequence among subjects who initiated the 3 groups of substances was the 'gateway' sequence T x2192; C x2192; OID, this pattern was not associated with substance use propensity more than alternative sequences. Early use propensity was associated with the 'gateway' sequence but also with some alternative ones beginning with T, C or OID. CONCLUSION: If the gateway sequence appears as the most likely pattern, in line with GT, the effects of early onset and substance use propensities were also observed for some alternative sequences, which is more in line with CLM. RAM could explain reciprocal interactions observed between T and C. This suggests shared influences of individual (personality traits) and environmental (substance availability, peer influence) characteristics.

Whole-body Vibration Exposure of Drill Operators in Iron Ore Mines and Role of Machine-Related, Individual, and Rock-Related Factors.

BACKGROUND: This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. METHODS: The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration (m/s(2))], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. RESULTS: More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient ß = -0.052, standard error SE = 0.023), manufacturer (ß = 1.093, SE = 0.227), rock hardness (ß = 0.045, SE = 0.018), uniaxial compressive strength (ß = 0.027, SE = 0.009), and density (ß = -1.135, SE = 0.235). CONCLUSION: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

Gender and family disparities in suicide attempt and role of socioeconomic, school, and health-related difficulties in early adolescence.

Suicide attempt (SA) is common in early adolescence and the risk may differ between boys and girls in nonintact families partly because of socioeconomic, school, and health-related difficulties. This study explored the gender and family disparities and the role of these covariates. Questionnaires were completed by 1,559 middle-school adolescents from north-eastern France including sex, age, socioeconomic factors (family structure, nationality, parents' education, father's occupation, family income, and social support), grade repetition, depressive symptoms, sustained violence, sexual abuse, unhealthy behaviors (tobacco/alcohol/cannabis/hard drug use), SA, and their first occurrence over adolescent's life course. Data were analyzed using Cox regression models. SA affected 12.5% of girls and 7.2% of boys (P < 0.001). The girls living with parents divorced/separated, in reconstructed families, and with single parents had a 3-fold higher SA risk than those living in intact families. Over 63% of the risk was explained by socioeconomic, school, and health-related difficulties. No family disparities were observed among boys. Girls had a 1.74-time higher SA risk than boys, and 45% of the risk was explained by socioeconomic, school, and mental difficulties and violence. SA prevention should be performed in early adolescence and consider gender and family differences and the role of socioeconomic, school, and health-related difficulties.