A Comparison of Variable- and Person-Oriented Approaches in Evaluating a Universal Preventive Intervention.

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.

Obtaining deeper insights into microbiome diversity using a simple method to block host and nontargets in amplicon sequencing.

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.

Characterization of the total and viable bacterial and fungal communities associated with the International Space Station surfaces.

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.

Microbial succession in an inflated lunar/Mars analog habitat during a 30-day human occupation.

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.

Childhood injury rates in Manitoba: socioeconomic influences.

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.

Factors affecting adolescent reproductive health in Manitoba.

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 low-income 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.

Being born in Manitoba: a look at perinatal health issues.

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 (< 2500 g) was 5.3%, from 2.7% to 5.7% by RHA, and 4.4% to 7.2% by Winnipeg CA. The lower the income, the greater the likelihood of low birthweight (p < 0.05). Manitoba's breastfeeding initiation rate was 78%, from 64% to 87% by RHA, and 66% to 90% by Winnipeg CA. The lower the income and the poorer the health status of the population, the lower the breastfeeding rate (p < 0.001). Of those initiating breastfeeding, 42% breastfed for at least six months. CONCLUSION: Factors affecting child health in Manitoba could be addressed through systematic programs both during pregnancy and during the postpartum period, including support for nutritional counselling, promotion of breastfeeding, smoking cessation programs, and social policy decisions designed to overcome disparities within low-income groups and populations with poorer health status.

Health service utilization by Manitoba children.

OBJECTIVE: To compare physician and hospital utilization rates by children across subregions of Manitoba. METHODS: 1998/99 data for physician visits and hospitalizations for children aged 0 to 19 were extracted from the Population Health Research Data Repository. Rates of utilization were compared across 12 regions (RHAs) within Manitoba, and 12 community areas within Winnipeg. Rates were also compared across premature mortality rates (PMR) and area income levels. RESULTS: Substantial regional variation was found for utilization rates. The hospitalization rate for children from the three northern RHAs (highest PMRs) (114/1000) was almost four times the Winnipeg rate (30/1000) and almost double the rate for the rural south RHAs (lowest PMRs) (59/1000). The variation among regions in physician visits ranged from under 2 visits in 2 of the northern RHAs to almost 4 visits in urban areas. However, the low visit rates in rural RHAs are offset somewhat by greater use of nurses. Hospitalizations and physician visits were also related to area income level. CONCLUSION: Findings are discussed in terms of health care need.

Community resources and determinants of the future health of Manitobans.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: We documented regional variation in the availability of resources to support healthy childhood development.

Using a population-based health information system to study child health.

OBJECTIVE: This paper describes the population-based analyses of measures of child health status used throughout this supplement. METHODS: The articles in this supplement examine health-related data for children 0 to 19 years. Most analyses cover the period from April 1, 1994 to March 31, 1999. Administrative and survey data were used to assess child health and well-being. For regional comparisons, data were broken down by subregions of Manitoba, called Regional Health Authorities (RHAs), and neighbourhoods of Winnipeg, called Winnipeg Community Areas (Winnipeg CAs). The premature mortality rate (PMR) was used as a proxy of the overall health of the population. All graphs comparing rates among RHAs and Winnipeg CAs rank these subregions in the same order, from lowest to highest PMR. Income was operationalized by dividing the province's population into urban and rural quintiles based upon household income. Other aspects of methodology are discussed. RESULTS: Results are presented in the articles that follow this one. CONCLUSION: The relationships between key child health indicators and geographic and socioeconomic factors for Manitoba children are discussed in the articles following this one.

Effectiveness of peer-based healthy living lesson plans on anthropometric measures and physical activity in elementary school students: a cluster randomized trial.

IMPORTANCE: 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. OBJECTIVE: 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. DESIGN, SETTING, AND PARTICIPANTS: 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). INTERVENTION: 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. MAIN OUTCOMES AND MEASURES: 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. RESULTS: 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. CONCLUSIONS AND RELEVANCE: 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. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01979978.

The incidence of methylphenidate use by Canadian children: what is the impact of socioeconomic status and urban or rural residence?

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.