RESUMO
BACKGROUND: The objective of this study is to find temporal trends in the associations between cardiovascular disease and occupational risk factors in the context of the Canadian population. METHODS: Population data were analyzed from the Canadian Community Health Survey (CCHS) collected between 2001 and 2014 for trends over time between heart disease and various occupational risk factors: hours worked, physical exertion at work, and occupation type (management/arts/education, business/finance, sales/services, trades/transportations, and primary industry/processing). RESULTS: We found no significant difference in the average number of hours worked/wk between individuals who report having heart disease in all years of data except in 2011 (F1,96 = 7.02, p = 0.009) and 2012 (F1,96 = 8.86, p = 0.004). We also found a significant difference in the degree of physical exertion at work in 2001 (F1,79 = 7.45, p = 0.008). There were statistically significant results of occupation type on self-reported heart disease from 2003 to 2014. CONCLUSION: Canadian data from the CCHS do not exhibit a trend toward an association between heart disease and the number of hours worked/wk. There is an association between heart disease and physical exertion at work, but the trend is inconsistent. The data indicate a trend toward an association between heart disease and occupation type, but further analysis is required to determine which occupation type may be associated with heart disease.
RESUMO
BACKGROUND: Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT) in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina. METHODS & RESULTS: A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5) deletion of VAChT (VAChTSix3-Cre-flox/flox) and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP) amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses. SIGNIFICANCE: This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina.