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There are currently over 80 species of mosquito endemic in Canada-although only a few of these carry pathogens that can cause disease in humans. West Nile virus, Eastern equine encephalitis virus and the California serogroup viruses (including the Jamestown Canyon and snowshoe hare viruses) are mosquito-borne viruses that have been found to cause human infections in North America, including in Canada. Over the last 20 years, the incidence of most of these endemic mosquito-borne diseases (MBD) has increased approximately 10% in Canada, due in large part to climate change. It is anticipated that both the mosquito lifecycle and virus transmission patterns will be affected by climate change, resulting in an increase in both the range and local abundance of several important mosquito species. Laboratory studies and mathematical modelling suggest that increased ambient temperatures, changes in precipitation and extreme weather events associated with climate change will likely continue to drive mosquito vector and MBD range expansion, increasing the duration of transmission seasons and leading to MBD-related epidemics. Furthermore, Canada's endemic MBDs have complex transmission cycles, involving multiple reservoir hosts (birds and mammals), multiple pathogens and multiple mosquito species-all of which may be sensitive to climate and other environmental changes, and making forecasting of potential emerging trends difficult. These expected climate-induced changes in mosquitoes and MBDs underline the need for continued (and expanded) surveillance and research to ensure timely and accurate evaluation of the risks to the public health of Canadians. [ABSTRACT FROM AUTHOR]

Aim To investigate the association between changes in oestradiol and follicle-stimulating hormone levels during the menopausal transition and incident diabetes. Methods We followed 1407 pre-menopausal women, aged 42-52 years at baseline, who experienced natural menopause, from baseline to the 12th annual follow-up visit in the Study of Women's Health Across the Nation ( SWAN). Diabetes was defined based on fasting glucose level, medication use and self-report of physician diagnosis. Cox proportional hazards regression was used to evaluate the associations of incident diabetes with three components of the rate of change in hormones: the intercept (pre-menopausal levels) and two piece-wise slopes representing change during the early and late transition, respectively. Results During 15 years of follow-up, 132 women developed diabetes. After adjusting for potential confounders, a higher oestradiol intercept, but not its rate of change, was borderline significantly associated with lower risk of diabetes [hazard ratio for an interquartile range increase (75.2 pmol/L) 0.53, 95% CI 0.27-1.06]. For follicle-stimulating hormone, a greater rate of increase in the early transition, but not the intercept or late transition, was significantly associated with lower risk of diabetes [hazard ratio for an interquartile range increase (5.9 IU/L/year) 0.31, 95% CI 0.10-0.94]. Conclusions Lower pre-menopausal oestradiol levels and a slower rate of follicle-stimulating hormone change during the early transition were associated with higher risk of developing diabetes. Given that obesity plays an important role in diabetes risk and in the levels and changes in oestradiol and follicle-stimulating hormone over the menopausal transition, weight control in earlier mid-life is important to prevent future diabetes development. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic poses a serious threat to global health, and pathogenic mutations are a major challenge to disease control. We developed a statistical framework to explore the association between molecular-level mutation activity of SARS-CoV-2 and population-level disease transmissibility of COVID-19., Methods: We estimated the instantaneous transmissibility of COVID-19 by using the time-varying reproduction number (R t ). The mutation activity in SARS-CoV-2 is quantified empirically depending on (i) the prevalence of emerged amino acid substitutions and (ii) the frequency of these substitutions in the whole sequence. Using the likelihood-based approach, a statistical framework is developed to examine the association between mutation activity and R t . We adopted the COVID-19 surveillance data in California as an example for demonstration., Results: We found a significant positive association between population-level COVID-19 transmissibility and the D614G substitution on the SARS-CoV-2 spike protein. We estimate that a per 0.01 increase in the prevalence of glycine (G) on codon 614 is positively associated with a 0.49% (95% CI: 0.39 to 0.59) increase in R t , which explains 61% of the R t variation after accounting for the control measures. We remark that the modeling framework can be extended to study other infectious pathogens., Conclusions: Our findings show a link between the molecular-level mutation activity of SARS-CoV-2 and population-level transmission of COVID-19 to provide further evidence for a positive association between the D614G substitution and R t . Future studies exploring the mechanism between SARS-CoV-2 mutations and COVID-19 infectivity are warranted.

Objective: The aim of this paper was to identify shapes of the curves between weekly working hours (WWH) and mental health status (MHS) and determine WWH for the best MHS in 13 occupations., Methods: This cross-sectional study applied public data of the 2015 to 2016 California Health Interview Survey. Restricted cubic spline regression was used to determine non-linear trends., Results: A statistically significant nearly V-shaped curve was demonstrated between WWH and MHS in total population, men and management, business and finance occupations. WWH for the best MHS were 42, 45, and 46 hours, respectively., Conclusion: These results suggest MHS be susceptible to WWH in total population, men and management, business and finance occupations. WWH for the best MHS for relevant populations could provide evidence for better work hours regulations in California.

Background: Policies protecting children from exposure to secondhand smoke (SHS) may help prevent SHS-related negative health outcomes in children and discourage them from intending to smoke in the future. In this study, we assess the impact of California's 2007 smoke-free vehicle law on changes in middle and high school students' reported exposure to smoking in cars. Secondary aims included assessing the association of student-reported exposure to smoking in vehicles and lifetime asthma diagnosis and future intentions to smoke., Methods: Population-weighted data from the California Student Tobacco Survey and the National Youth Tobacco Survey were used to evaluate California and national trends, respectively. Weighted logistic regression models using California Student Tobacco Survey 2011 data assessed the association between the number of days of exposure to smoking in cars and student-reported lifetime asthma diagnosis as well as intention to smoke in the future., Results: The proportion of California students reporting exposure to smoking in cars in the last 7 days declined <1% annually from 2001 through 2005, but declined 12% annually from 2007 to 2011. National trends did not show comparable declines after 2006. Students reporting exposure to smoking in vehicles were more likely to report having ever been diagnosed with asthma and intending to smoke in the future than students who were not exposed to SHS., Conclusions: These findings support the legislative intent that public policies that are designed to protect children from exposure to smoking in vehicles will yield better adolescent health outcomes and a lower risk of future adolescent cigarette smoking., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2018 by the American Academy of Pediatrics.)

Objective: To profile hospitals by survival rates of colorectal cancer patients in multiple periods after initial treatment., Data Sources: California Cancer Registry data from 50,544 patients receiving primary surgery with curative intent for stage I-III colorectal cancer in 1994-1998, supplemented with hospital discharge abstracts., Study Design: We estimated a single Bayesian hierarchical model to quantify associations of survival to 30 days, 30 days to 1 year, and 1-5 years by hospital, adjusted for patient age, sex, race, stage, tumor site, and comorbidities. We compared two profiling methods for 30-day survival and four longer-term profiling methods by the fractions of hospitals with demonstrably superior survival profiles and of hospital pairs whose relative standings could be established confidently., Principal Findings: Interperiod correlation coefficients of the random effects are (95 percent credible interval 0.27, 0.85), (0.20, 0.76), and (0.19, 0.82). The three-period model ranks 5.4 percent of pairwise comparisons by 30-day survival with at least 95 percent confidence, versus 3.3 percent of pairs using a single-period model, and 15-20 percent by weighted multiperiod methods., Conclusions: The quality of care for colorectal cancer provided by a hospital system is somewhat consistent across the immediate postoperative and long-term follow-up periods. Combining mortality profiles across longer periods may improve the statistical reliability of outcome comparisons., (© Health Research and Educational Trust.)

Objectives: We examined the relationship between students' tobacco use and the density and proximity of tobacco retailers near their schools., Methods: We used data from the 2003-2004 California Student Tobacco Survey and California retail licensing data. Measures included students' self-reported tobacco use and geocoded state-reported locations of tobacco retailers. We used random-intercept generalized linear mixed modeling to jointly evaluate individual-level and school-level predictors., Results: Density of retailers was associated with experimental smoking (odds ratio [OR] = 1.11; 95% confidence interval [CI] = 1.02, 1.21) but not established smoking (OR = 1.06; 95% CI = 0.94, 1.20). The effects on experimental smoking were confined to high school students (OR = 1.17; 95% CI = 1.06, 1.29) in urban areas (OR = 1.11; 95% CI = 1.01, 1.21); no effects were observed among middle school students or in rural schools. High school students were more likely to obtain cigarettes from a retailer; middle school students relied more heavily on social sources., Conclusions: Our results support the plausibility of reducing rates of students' experimental smoking, but not established smoking, by restricting their access to commercial sources of tobacco in urban areas.