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SummaryVariable phenotypes help plants ensure fitness and survival in the face of unpredictable environmental stresses. Leaf bacteria (bacteriomes) can extend plant phenotypes and are well-known to vary from one plant to the next, but little is known about controls on this variation. Here, we find in 9 populations of Arabidopsis thaliana that core leaf bacteriomes are largely, but not completely, shared with other ground-dwelling ruderal plant species. Strength of differentiation between plant species and between A. thaliana populations shifts from year to year, becoming stronger when plants within populations have more similar leaf bacteriomes (less plant-to-plant variation or stochasticity). Interestingly, across different populations, plants with shared leaf aliphatic glucosinolate chemotypes exhibited similar strong year-to-year stochasticity shifts. Therefore, stochasticity of leaf bacteriomes in plant populations changes in specific ways and might be controlled by plant traits, with important implications for how plants adapt to complex and shifting environments.

International audience; Profiling diverse microbiomes is revolutionizing our understanding of biological mechanisms and ecologically relevant problems, including metaorganism (host + microbiome) assembly, functions and adaptation. Amplicon sequencing of multiple conserved, phylogenetically informative loci has therefore become an instrumental tool for many researchers. Investigations in many systems are hindered, however, since essential sequencing depth can be lost by amplification of nontarget DNA from hosts or overabundant microorganisms. Here, we introduce “blocking oligos”, a low-cost and flexible method using standard oligonucleotides to block amplification of diverse nontargets and software to aid their design. We apply them primarily in leaves, where exceptional challenges with host amplification prevail. A. thaliana-specific blocking oligos applied in eight different target loci reduce undesirable host amplification by up to 90%. To expand applicability, we designed universal 16S and 18S rRNA gene plant blocking oligos for targets that are conserved in diverse plant species and demonstrate that they efficiently block five plant species from five orders spanning monocots and dicots (Bromus erectus, Plantago lanceolata, Lotus corniculatus, Amaranth sp., Arabidopsis thaliana). These can increase alpha diversity discovery without biasing beta diversity patterns and do not compromise microbial load information inherent to plant-derived 16S rRNA gene amplicon sequencing data. Finally, we designed and tested blocking oligos to avoid amplification of 18S rRNA genes of a sporulating oomycete pathogen, demonstrating their effectiveness in applications well beyond plants. Using these tools, we generated a survey of the A. thaliana leaf microbiome based on eight loci targeting bacterial, fungal, oomycete and other eukaryotic microorganisms and discuss complementarity of commonly used amplicon sequencing regions for describing leaf microbiota. This approach has potential to make questions in a variety of study systems more tractable by making amplicon sequencing more targeted, leading to deeper, systems-based insights into microbial discovery. For fast and easy design for blocking oligos for any nontarget DNA in other study systems, we developed a publicly available R package.

Background The International Space Station (ISS) is a closed system inhabited by microorganisms originating from life support systems, cargo, and crew that are exposed to unique selective pressures such as microgravity. To date, mandatory microbial monitoring and observational studies of spacecraft and space stations have been conducted by traditional culture methods, although it is known that many microbes cannot be cultured with standard techniques. To fully appreciate the true number and diversity of microbes that survive in the ISS, molecular and culture-based methods were used to assess microbial communities on ISS surfaces. Samples were taken at eight pre-defined locations during three flight missions spanning 14 months and analyzed upon return to Earth. Results The cultivable bacterial and fungal population ranged from 104 to 109 CFU/m2 depending on location and consisted of various bacterial (Actinobacteria, Firmicutes, and Proteobacteria) and fungal (Ascomycota and Basidiomycota) phyla. Amplicon sequencing detected more bacterial phyla when compared to the culture-based analyses, but both methods identified similar numbers of fungal phyla. Changes in bacterial and fungal load (by culture and qPCR) were observed over time but not across locations. Bacterial community composition changed over time, but not across locations, while fungal community remained the same between samplings and locations. There were no significant differences in community composition and richness after propidium monoazide sample treatment, suggesting that the analyzed DNA was extracted from intact/viable organisms. Moreover, approximately 46% of intact/viable bacteria and 40% of intact/viable fungi could be cultured. Conclusions The results reveal a diverse population of bacteria and fungi on ISS environmental surfaces that changed over time but remained similar between locations. The dominant organisms are associated with the human microbiome and may include opportunistic pathogens. This study provides the first comprehensive catalog of both total and intact/viable bacteria and fungi found on surfaces in closed space systems and can be used to help develop safety measures that meet NASA requirements for deep space human habitation. The results of this study can have significant impact on our understanding of other confined built environments on the Earth such as clean rooms used in the pharmaceutical and medical industries. Electronic supplementary material The online version of this article (10.1186/s40168-019-0666-x) contains supplementary material, which is available to authorized users.

Evaluations of prevention programs, such as the PAX Good Behavior Game (PAX), often have multiple outcome variables (e.g., emotional, behavioral, and relationship problems). These are often reported for multiple time points (e.g., pre- and post-intervention) where data are multilevel (e.g., students nested in schools). In this paper, we present both variable-oriented and person-oriented statistical approaches, to evaluate an intervention program with multilevel, longitudinal multivariate outcomes. Using data from the Manitoba PAX Study, we show how these two approaches provide us with different information that can be complementary. Data analyses with the variable-oriented approach (multilevel linear regression model) provided us with overall PAX program effects for each outcome variable; the person-oriented approach (latent transition analysis) allowed us to explore the transition of multiple outcomes across multiple time points and how the intervention program affects this transition differently for students with different risk profiles. We also used both approaches to examine how gender and socio-economic status related to the program effects. The implications of these results and the use of both types of approaches for program evaluation are discussed.

Background An inflatable lunar/Mars analog habitat (ILMAH), simulated closed system isolated by HEPA filtration, mimics International Space Station (ISS) conditions and future human habitation on other planets except for the exchange of air between outdoor and indoor environments. The ILMAH was primarily commissioned to measure physiological, psychological, and immunological characteristics of human inhabiting in isolation, but it was also available for other studies such as examining its microbiological aspects. Characterizing and understanding possible changes and succession of fungal species is of high importance since fungi are not only hazardous to inhabitants but also deteriorate the habitats. Observing the mycobiome changes in the presence of human will enable developing appropriate countermeasures with reference to crew health in a future closed habitat. Results Succession of fungi was characterized utilizing both traditional and state-of-the-art molecular techniques during the 30-day human occupation of the ILMAH. Surface samples were collected at various time points and locations to observe both the total and viable fungal populations of common environmental and opportunistic pathogenic species. To estimate the cultivable fungal population, potato dextrose agar plate counts method was utilized. The internal transcribed spacer region-based iTag Illumina sequencing was employed to measure the community structure and fluctuation of the mycobiome over time in various locations. Treatment of samples with propidium monoazide (PMA; a DNA intercalating dye for selective detection of viable microbial populations) had a significant effect on the microbial diversity compared to non-PMA-treated samples. Statistical analysis confirmed that viable fungal community structure changed (increase in diversity and decrease in fungal burden) over the occupation time. Samples collected at day 20 showed distinct fungal profiles from samples collected at any other time point (before or after). Viable fungal families like Davidiellaceae, Teratosphaeriaceae, Pleosporales, and Pleosporaceae were shown to increase during the occupation time. Conclusions The results of this study revealed that the overall fungal diversity in the closed habitat changed during human presence; therefore, it is crucial to properly maintain a closed habitat to preserve it from deteriorating and keep it safe for its inhabitants. Differences in community profiles were observed when statistically treated, especially of the mycobiome of samples collected at day 20. On a genus level Epiccocum, Alternaria, Pleosporales, Davidiella, and Cryptococcus showed increased abundance over the occupation time. Electronic supplementary material The online version of this article (doi:10.1186/s40168-017-0280-8) contains supplementary material, which is available to authorized users.

Background For potential future human missions to the Moon or Mars and sustained presence in the International Space Station, a safe enclosed habitat environment for astronauts is required. Potential microbial contamination of closed habitats presents a risk for crewmembers due to reduced human immune response during long-term confinement. To make future habitat designs safer for crewmembers, lessons learned from characterizing analogous habitats is very critical. One of the key issues is that how human presence influences the accumulation of microorganisms in the closed habitat. Results Molecular technologies, along with traditional microbiological methods, were utilized to catalog microbial succession during a 30-day human occupation of a simulated inflatable lunar/Mars habitat. Surface samples were collected at different time points to capture the complete spectrum of viable and potential opportunistic pathogenic bacterial population. Traditional cultivation, propidium monoazide (PMA)–quantitative polymerase chain reaction (qPCR), and adenosine triphosphate (ATP) assays were employed to estimate the cultivable, viable, and metabolically active microbial population, respectively. Next-generation sequencing was used to elucidate the microbial dynamics and community profiles at different locations of the habitat during varying time points. Statistical analyses confirm that occupation time has a strong influence on bacterial community profiles. The Day 0 samples (before human occupation) have a very different microbial diversity compared to the later three time points. Members of Proteobacteria (esp. Oxalobacteraceae and Caulobacteraceae) and Firmicutes (esp. Bacillaceae) were most abundant before human occupation (Day 0), while other members of Firmicutes (Clostridiales) and Actinobacteria (esp. Corynebacteriaceae) were abundant during the 30-day occupation. Treatment of samples with PMA (a DNA-intercalating dye for selective detection of viable microbial population) had a significant effect on the microbial diversity compared to non-PMA-treated samples. Conclusions Statistical analyses revealed a significant difference in community structure of samples over time, particularly of the bacteriomes existing before human occupation of the habitat (Day 0 sampling) and after occupation (Day 13, Day 20, and Day 30 samplings). Actinobacteria (mainly Corynebacteriaceae) and Firmicutes (mainly Clostridiales Incertae Sedis XI and Staphylococcaceae) were shown to increase over the occupation time period. The results of this study revealed a strong relationship between human presence and succession of microbial diversity in a closed habitat. Consequently, it is necessary to develop methods and tools for effective maintenance of a closed system to enable safe human habitation in enclosed environments on Earth and beyond. Electronic supplementary material The online version of this article (doi:10.1186/s40168-016-0167-0) contains supplementary material, which is available to authorized users.

Evaluations of intervention programs, such as the PAX Good Behaviour Game (PAX) program often have multiple outcome variables (e.g., emotional symptoms, conduct problems, hyperactivity/inattention, peer relationship problems, and prosocial behaviour). These are often reported for multiple time points (e.g., pre- and post-intervention) where data are multilevel (e.g., students nested in schools). In this paper, we use latent transition analysis (LTA), a person-oriented statistical approach, to evaluate the PAX program with multilevel, longitudinal multivariate outcomes. Using data from the Manitoba PAX Study, we show how LTA helps explore the transition of multiple outcomes across multiple time points and how the intervention program affects this transition. The strengths and limitations of LTA are discussed.

Objective: To examine socioeconomic, demographic, and behavioural factors that influence the incidence of methylphenidate use among children aged 4 to 13 years. Method: A total of 11 316 children, aged 2 through 11 years, from Cycle 1 (1994-95) of the National Longitudinal Survey of Children and Youth were followed up 2 years later in Cycle 2 (1996-97). The outcome measure was methylphenidate use in Cycle 2. Individual-level explanatory variables included sex, age, socioeconomic status (SES), mother's age at birth of child, lone-parent family status, parental working status, and hyperactivity-impulsivity and inattention probabilities. Area-level explanatory variables included income and rural or urban residence. We used hierarchical linear modelling to examine individual- and area-level factors that predicted methylphenidate use. Results: The strongest predictors of methylphenidate use were behavioural: children with high hyperactive-impulsive and (or) inattention behaviours in 1994, compared with children low on these behaviours, were 4.5 to 6 times more likely to use methylphenidate 2 years later. SES remained a significant predictor of the incidence of methylphenidate use, even when other significant predictors were held constant, with lower SES being associated with higher use. Area-level income also predicted methylphenidate use. Conclusion: Even when children with similar behavioural symptoms and demographic characteristics were compared, socioeconomic factors had a significant impact on incidence of methylphenidate use. (Can J Psychiatry 2006;51:847-854) Information on funding and support and author affiliations appears at the end of this article. Clinical Implications * The strongest predictors of the incidence of methylphenidate use were hyperactive-impulsive and inattentive behaviours. * SES remained a significant predictor of methylphenidate use, even when the behavioural and other significant predictors were held constant. Children with lower SES were more likely to use methylphenidate, and as SES increased, the likelihood of methylphenidate use decreased. * Even for children who came from families with similar individual-level SES, the likelihood of taking methylphenidate was 2 times higher if the children lived in the lowest income, compared with the highest income, areas. Limitations * The NLSCY does not ask whether children have been diagnosed with ADHD. * The NLSCY relies on parental reports of methylphenidate use; some parents may be reluctant to report use. * The NLSCY asks only about methylphenidate use; children taking other stimulants, such as dextroamphetamine, may be excluded from the study. Key Words: attention-deficit hyperactivity disorder, methylphenidate, socioeconomic status, hyperactivity, inattention, impulsivity Abbreviations used in this article ADHD attention deficit hyperactivity disorder NLSCY National Longitudinal Survey of Children and Youth PMK person most knowledgeable SES socioeconomic status OR odds ratio Resume : L'incidence de l'utilisation du methylphenidate par les enfants canadiens : quelle est l'influence du statut socio-economique et du lieu de residence urbain ou rural? Objectif : Examiner les facteurs socio-economiques, demographiques et comportementaux qui influent sur l'incidence de l'utilisation du methylphenidate chez les enfants de 4 a 13 ans. Methode : Un total de 11 316 enfants, de 2 a 11 ans, du cycle 1 (1994-1995) de l'Enquete longitudinale nationale sur les enfants et les jeunes (ELNEJ) ont ete suivis 2 ans plus tard, dans le cadre du cycle 2 (1996-1997). La mesure du resultat etait celle de l'utilisation du methylphenidate dans le cycle 2. Les variables explicatives au niveau individuel comprenaient le sexe, l'âge, le statut socio-economique (SSE), l'âge de la mere a la naissance de l'enfant, la situation familiale monoparentale, la situation professionnelle des parents, et les probabilites d'hyperactivite-impulsivite et d'inattention. …

OBJECTIVE: The Manitoba Centre for Health Policy was commissioned by Manitoba’s provincial health department to examine the health of newborns born 1994 through 1998, using three indicators: preterm birth (37 weeks gestation), birthweight, and type of infant feeding. METHODS: Data were derived from the Population Health Research Data Repository and the National longitudinal Survey of Children and Youth 1996. Variation by 12 Regional Health Authorities (RHAs) and by 12 Winnipeg Community Areas (CAs) was examined, as well as associations with the population’s health and socioeconomic well-being. RESULTS: Manitoba’s preterm birth rate was 6.7% of live births, from 5.3% to 7.4% by RHA, and 5.7% to 8.0% by Winnipeg CA. Manitoba’s low birthweight rate (

The association between injurious falls requiring hospitalization and selected classes of medications was examined in a case-control study of nursing home residents. Information for this study was obtained exclusively from four computerized administrative databases. Over the period from April 1987 to March 1992, a total of 1,560 first injurious falls occurred to 14,744 residents of Manitoba, Canada, nursing homes who were eligible for inclusion in the study. An injurious fall was defined as an injury consequent to a fall that resulted in admission to the hospital for treatment. Medication use was ascertained from prescription information contained in computerized dispensing records from community pharmacies. Three series of single controls were pair-matched to each case, implementing increasing stringent matching on age, sex, level of dependency, duration of residence, and the presence of up to five chronic disorders. Estimates of relative odds obtained from the most stringently matched case-control series identified two medication classes in which a prescription dispensed in the previous 30 days was associated with an elevated risk of injurious fall: antipsychotic agents (odds ratio = 1.31, 95 percent confidence interval 1.06-1.61) and anxiolytics/sedatives/ hypnotics (odds ratio = 1.35, 95 percent confidence interval 1.09-1.68). An unexpected protective effect was associated with the use inotropic agents (odds ratio = 0.69, 95 percent confidence interval 0.54-0.89). These results support the hypothesis that psychotropic medications are an independent risk factor for injurious falls in nursing home settings.

OBJECTIVES: To report teen pregnancy and sexually transmitted infections (STI) rates among Manitoba adolescents, and associated factors including rates of sexual intercourse and contraceptive use. METHODS: Teen pregnancy rates in females aged 15 to 19 for the fiscal years 1994/95 through 1998/99 were derived from the Population Health Research Data Repository and reported by geographical areas and income quintiles. Premature mortality rate (PMR) and the Socioeconomic Factor Index (SEFI) measured the overall health and socioeconomic well-being of regional populations. Data on sexual activity and contraceptive use were derived from the 1996 National Population Health Survey for males and females ages 15 through 19 years. RESULTS: The teen pregnancy rate for Manitoba was 63.2/1000, varying by geography and inversely correlated with income, PMR, and SEFI. 39% (95% CI 33-45) of teens reported sexual intercourse, with higher rates in urban areas (46%, 95 % CI 35-57) and the North (48%, 95% CI 36-60) compared to South Rural (30%, 95% CI 25-34), and in low-income families (68%, 95% CI 53-83) compared with middle/high (33%, 95% CI 26-40). For sexually active females, 42% (95% CI 28-57) used the birth control pill, with higher rates in low-income families (70%, 95% CI 50-90) compared to middle/high income (31%, 95% CI 14-48). Condom use (at last sexual intercourse) was reported by 82% (95% CI 72-92) of adolescents, with trends (though not statistically significant) to lower use in lowincome families and the North. CONCLUSION: Reliance on the pill for contraception, combined with low rates of condom use, are public health concerns for adolescents where STI and unintended pregnancy rates are high.

BACKGROUND: Injury is the leading cause of death among Canadian children between 1 and 19 years, and accounts for one sixth of all hospitalizations of children between 0 and 19 years. We examined the causes of injury in Manitoba children, and the relationship between injury rates and region of residence, premature mortality rate (PMR), and income. METHODS: Regional differences in injury death and hospitalization rates, and causes of injury were derived from the Population Health Research Data Repository. The relationship between injury rates and area income levels was assessed and correlations between regional premature mortality rates (PMR) and injury rates were calculated. RESULTS: Motor vehicle crashes were the leading cause of injury mortality. Falls were the leading cause of injury hospitalization. Regional differences were substantial. Rural-urban differences in injury rates were pronounced; northern Manitoba’s rates were very high compared to the rest of the province. Regional PMR values correlated significantly with injury mortality and hospitalization rates. Both types of injury rates correlated significantly with income; higher injury rates were associated with lower income levels. CONCLUSION: Injuries are not random events, but are related to social factors.

Schools are considered an attractive setting to promote healthy living behaviors in children, but previous school-based interventions aimed at preventing weight gain in children have yielded mixed results. Novel school-based approaches are needed to modify healthy living behaviors and attenuate weight gain in children.To assess the effectiveness of a peer-led healthy living program called Healthy Buddies on weight gain and its determinants when disseminated at the provincial level to elementary school students.Cluster-randomized effectiveness trial performed during the 2009-2010 school year. Baseline and follow-up measurements were made in October 2009 and May 2010, respectively. The study was performed in 19 elementary schools in Manitoba, Canada, and included 647 elementary school students aged 6 to 12 years (48% girls).Schools were randomized to receive regular curriculum or Healthy Buddies lesson plans. Lesson plans were delivered by older (9- to 12-year-old) elementary school students to the younger (6- to 8-year-old) peers and targeted 3 components of health: physical activity, healthy eating, and self-esteem and body image.The primary outcome measures were the change in waist circumference and body mass index z score. Secondary outcomes included physical activity (steps per day), cardiorespiratory fitness, self-efficacy, healthy living knowledge, and self-reported dietary intake.At baseline, 36% of children were overweight or obese and 11% achieved the recommended 13,500 steps per day. Intention-to-treat analyses showed that waist circumference declined significantly in the intervention group relative to controls: -1.42 cm (-2.68 to -0.17; P = .03). Reductions in waist circumference were particularly significant for children who were younger, overweight or obese, or attending First Nations schools. No difference in body mass index z score was observed between groups. Self-efficacy, healthy living knowledge, and dietary intake significantly improved in younger peers who received the intervention compared with students from control schools. No differences were observed in daily step counts or cardiorespiratory fitness between the groups.The implementation of Healthy Buddies lesson plans delivered by older peers within an elementary school setting is an effective method for attenuating increases in central adiposity and improving knowledge of healthy living behaviors among elementary school students. Improvements were achieved with parallel improvements in diet quality, self-efficacy, and knowledge of healthy living.clinicaltrials.gov Identifier: NCT01979978.

Sex differences in the use of health care services can be substantial at several stages of life. However, the extent to which differences in reproductive biology and mortality affect the use of health care services is unclear.We studied age- and sex-specific per capita use of health care resources for a one-year period during 1994 and 1995 in the Canadian province of Manitoba, where there is universal insurance for a comprehensive range of health care services. Using information obtained from administrative records of physicians' services and acute hospital care, we tabulated the use of health care resources by male and female subjects in three categories: care for conditions specific to sex, care provided to persons who died during the study year, and care provided for all other conditions.The crude annual per capita use of health care resources (in Canadian dollars) was greater for female subjects ($1,164) than for male subjects ($918). Approximately 22 percent of health care expenditures for female subjects was associated with conditions specific to sex, including pregnancy and childbirth, as compared with 3 percent of expenditures for male subjects. An estimated 14 percent of health care expenditures for male subjects was consumed by persons who died during the study period, as compared with 10 percent of expenditures for female subjects. After adjustment for the use of health care associated with sex-specific conditions and differences in mortality, the female:male ratio in health care expenditures was reduced from 1.3 to 1.0.Expenditures for health care are similar for male and female subjects after differences in reproductive biology and higher age-specific mortality rates among men have been accounted for.

Objective. To describe the prevalence of continuity of care over a 5-year period in a complete cohort of urban children universally insured for medical care provided under fee-for-service reimbursement. Method. All children enrolled in the study were born to women living in metropolitan Winnipeg between July 1,1987 and December 31, 1988 (N = 12 590). All ambulatory physician services for this group were enumerated from computerized administrative databases for the period from birth through 60 months. Continuity of care, defined as the proportion of total care provided by the most frequently seen physician or physician practice over time, was calculated for each child. Descriptive analyses include an examination of maternal and household characteristics associated with children receiving 80% or more of total ambulatory care from a single provider source. Results. From birth to 24 months, 51% of children received at least 80% of ambulatory visits from a single provider practice. This proportion of the children declined to 28% at 25 through 60 months. Children living in low-income neighborhoods had poorer continuity profiles. Other household factors associated with poor continuity included young maternal age, single maternal marital status, residential mobility, and inadequate maternal use of prenatal medical care. Households affiliated with pediatric practices had better continuity profiles than households affiliated with general medical practices. Conclusion. Despite universal medical insurance, barriers to a longitudinally continuous relationship with a primary care provider remain in this setting. Although this study has emphasized the description of those barriers associated with household characteristics, there is evidence that factors related to the organization and delivery of medical care are also relevant.

Life history studies in health show that some of the key determinants of health inequalities lie in biological and social experiences at the earliest times of life. The objectives of this research were to describe the regional distribution of childhood determinants of adult health, such as school achievement, and the environments which contribute to their development.Using Manitoba data from the National Population Health Survey, the National Longitudinal Survey on Children and Youth, the Department of Education, Training and Youth, the Department of Family Services and Housing, the Library Association website and the Agriculture and Food website, the regional distribution of Grade 3 standards test scores and neighbourhood resources such as child care services, libraries, sports participation and food costs were determined for 12 Regional Health Authorities and 12 Winnipeg Community Areas, ranked by a measure of population healthiness, the premature mortality rate. Findings were also reported by income level and larger geographic regions.Children living in neighbourhoods with less healthy populations were more likely to have poorer school performance, as indicated by Grade 3 math standards test scores. They were-also more likely to change schools, less likely to participate in sports, and had decreased access to affordable food and licenced day care. They had similar access to library books as children living in more healthy neighbourhoods, although book lending rates were not measured.We documented regional variation in the availability of resources to support healthy childhood development.

BACKGROUND: Injury is the leading cause of death among Canadian children between 1 and 19 years, and accounts for one sixth of all hospitalizations of children between 0 and 19 years. We examined the causes of injury in Manitoba children, and the relationship between injury rates and region of residence, premature mortality rate (PMR), and income. METHODS: Regional differences in injury death and hospitalization rates, and causes of injury were derived from the Population Health Research Data Repository. The relationship between injury rates and area income levels was assessed and correlations between regional premature mortality rates (PMR) and injury rates were calculated. RESULTS: Motor vehicle crashes were the leading cause of injury mortality. Falls were the leading cause of injury hospitalization. Regional differences were substantial. Rural-urban differences in injury rates were pronounced; northern Manitoba's rates were very high compared to the rest of the province. Regional PMR values correlated significantly with injury mortality and hospitalization rates. Both types of injury rates correlated significantly with income; higher injury rates were associated with lower income levels. CONCLUSION: Injuries are not random events, but are related to social factors. Language: en