The Transition from Good to Poor Health: An Econometric Study of the Older Population

This is a study of the influence of socioeconomic factors on the state of health of older Canadians. Three years of panel data from the Survey of Labour and Income Dynamics are used to model the transition probabilities between good and poor health. Care is taken to avoid the problem of endogeneity of income in modelling its effects, and to adjust reported income to free it from its strong association with age at the time of the survey. Of particular note are the significant effects found for income, in spite of universal public health care coverage. Significant effects are found also for age, education, and other variables.Socioeconomic factors and health; older population; panel data

The Transition from Good to Poor Health: An Econometric Study of the Older Population

This is a study of the influence of socioeconomic factors on the state of health of older Canadians. Three years of panel data from the Survey of Labour and Income Dynamics are used to model the transition probabilities between good and poor health. Care is taken to avoid the problem of endogeneity of income in modelling its effects, and to adjust reported income to free it from its strong association with age at the time of the survey. Of particular note are the significant effects found for income, in spite of universal public health care coverage. Significant effects are found also for age, education, and other variables.Socio-economic factors and health; older population; panel data; SLID

Healthy Aging at Older Ages: Are Income and Education Important?

Being higher on the socioeconomic scale is correlated with being in better health, but is there is a causal relationship? Using three years of longitudinal data for individuals aged 50 and older from the Canadian Survey of Labour and Income Dynamics, we study the health transitions for those who were in good health in the first year, focussing especially on income and education. The initial good health restriction removes from the sample those whose incomes may have been affected by a previous history of poor health, thus avoiding a well known problem of econometric endogeneity. We then ask, for those in good health, whether later transitions in health status are related to socioeconomic status. We find that they are that changes in health status over the subsequent two years are related in particular to income and education.aging, health, income, education

Healthy Aging at Older Ages: Are Income and Education Important?

Being higher on the socioeconomic scale is correlated with being in better health, but is there is a causal relationship? Using three years of longitudinal data for individuals aged 50 and older from the Canadian Survey of Labour and Income Dynamics, we study the health transitions for those who were in good health in the first year, focussing especially on income and education. The initial good health restriction removes from the sample those whose incomes may have been affected by a previous history of poor health, thus avoiding a well known problem of econometric endogeneity. We then ask, for those in good health, whether later transitions in health status are related to socioeconomic status. We find that they are -- that changes in health status over the subsequent two years are related in particular to income and education.aging, health, income, education

Socioeconomic Influence on the Health of Older People: Estimates Based on Two Longitudinal Surveys

There is a strong positive relationship between socioeconomic status (SES) and health, but identifying the direction of causation is difficult. This study exploits the longitudinal nature of two Canadian surveys, the Survey of Labour and Income Dynamics and the National Population Health Survey, to study the link from SES to health. For people aged 50 and older who are initially in good health we examine whether changes in health status over the next two to four years are related to prior SES, as represented by income and education. Although the two surveys were designed for quite different purposes the evidence they yield with respect to the probability of remaining in good health is strikingly similar. Both suggest that SES does play a role, that the differences across SES groups are quantitatively significant, that the differences increase with age, and that they are much same for men and women.health; socioeconomic status; SLID; NPHS

Socioeconomic Influence on the Health of Older People: Estimates Based on Two Longitudinal Surveys

There is a strong positive relationship between socioeconomic status (SES) and health, but identifying the direction of causation is difficult. This study exploits the longitudinal nature of two Canadian surveys, the Survey of Labour and Income Dynamics and the National Population Health Survey, to study the link from SES to health. For people aged 50 and older who are initially in good health we examine whether changes in health status over the next two to four years are related to prior SES, as represented by income and education. Although the two surveys were designed for quite different purposes the evidence they yield with respect to the probability of remaining in good health is strikingly similar. Both suggest that SES does play a role, that the differences across SES groups are quantitatively significant, that the differences increase with age, and that they are much same for men and women.health; socioeconomic status; SLID; NPHS

Socioeconomic Influences on the Health of Older Canadians: Estimates Based on Two Longitudinal Surveys

It is well established that there is a positive statistical relationship between socioeconomic status (SES) and health but identifying the direction of causation is difficult. This study exploits the longitudinal nature of two Canadian surveys, the Survey of Labour and Income Dynamics and the National Population Health Survey, to study the link from SES to health (as distinguished from the health-to-SES link). For people aged 50 and older who are initially in good health we examine whether changes in health status over the next two to four years are related to prior SES, as represented by income and education. Although the two surveys were designed for different purposes and had different questions for income and health, the evidence they yield with respect to the probability of remaining in good health is similar. Both suggest that SES does play a role and that the differences across SES groups are quantitatively significant, increase with age, and are much the same for men and women.health transitions, income, education

Comparing the Accuracy of Egg Candling and Egg Flotation to Estimate the Hatching Date of Northern Bobwhite Clutches

Floating and candling avian eggs to assess hatch dates has been used successfully to estimate hatch dates for wild bird clutches for decades. However, there is a dearth of information assessing the accuracy of these techniques to estimate northern bobwhite (Colinus virginianus) hatch dates. We captured and fitted a hen bobwhites with very high frequency transmitters during January and February of 2011–2012. We monitored each bird twice weekly until nesting was initiated. We searched for the nest while the hen was away from the nest (i.e., feeding) to reduce potential abandonment. We used egg floatation and egg candling methods to attempt to estimate wild northern bobwhite clutches during the 2011–2012 nesting seasons. We used a mini MagLite© (97 lumens; Mag Instrument, Inc., Ontario, CA, USA) with the glass lens removed so eggs would sit near the bulb to increase the illumination. We used a dark green 68-cm x 137-cm towel to cover the observer in the field to reduce the naturally occurring light, which might have reduced the visibility of the chick embryo. We based age of the eggs (no. of days since the start of incubation) on the embryo growth stage at the time of nest discovery. We conducted egg flotation at the same time as candling. We used a 100-mL glass beaker with 100-mL of ambient temperature tap water to completely submerge the egg to estimate hatch date. We based the flotation estimation age on the angle at which the egg floated in the water. We also conducted a controlled laboratory experiment using pen-raised quail eggs collected from the breeding colony at the Quail-Tech Alliance breeding facility in Lubbock, Texas. We placed 110 eggs in a commercial incubator that was maintained at 37° C with 55% humidity for the duration of the study. We used 3 novice observers to determine the impact of observer bias on the techniques of estimating hatch date. We placed random groups of eggs (i.e., 5–15 eggs at a time until 110 eggs were obtained) into the incubator at a staggered rate to increase variation in the study. We used the same field techniques for hatch date estimation in the controlled study. We first floated eggs during both controlled and field observations to reduce any potential bias that candling might have on the hatch date estimation (i.e., lack of embryo growth). During the controlled study observers examined the eggs individually. Using the average estimated hatch date (Julian date) as a predictor, we used linear regression to determine the accuracy of the candling and floating methods. We also used a linear regression to determine the accuracy of each estimation technique and observers. When candle and egg floating occurred in a field setting, both methods were found to overestimate the actual hatch date of the clutches discovered (n = 47; R2 = 0.993, P \u3c 0.001; estimated hatch days when using candle: x̄ = 1.21 ± 0.92 days, floating: x̄ = 0.89 ± 0.97 days). However, the mean difference between the candling and flotation was -0.38 days (SE = 1.07 days). Regression analysis suggests that candling and egg flotation are fairly accurate predictors of the actual hatch date for newly discovered bobwhite nests (candling: β = 0.43, t = 3.75, P = 0.001; floating: β = 0.53, t = 4.79, P \u3c 0.001). Use of the candling method appears to be correct 43% of the time whereas egg flotation accurately predicted the estimated hatch date 53% of the time. Under controlled conditions, all 3 observers were new to both techniques of hatch date estimation and were all taught by the same instructor for each method. During the controlled test, we found that observers were highly variable. Two observers could predict the estimated hatch date by using the candling and egg flotation methods to a close estimation of the actual hatch date (floating [observer 1: β = 0.23, t = 2.80, P = 0.006 and observer 2: β = 0.47, t = 5.52, P \u3c 0.001]; candling [observer 1: β = 0.30, t = 4.00, P = 0.006, observer 2: β = 0.219, P \u3c 0.01]). Although observer 3 was unable to predict the estimated hatch date for both estimation methods (floating: β = –0.001, t = –0.013, P = 0.684; candling: β = 0.043, t = 0.40, P = 0.990). We also examined any potential abandonment or hatchability issues that might have risen while using candling or floating to estimate hatch dates for wild clutches. We found that 0.06% (5 of 80 nests) of hens abandoned their clutches during this study. Of the 5 nests that were abandoned zero were abandoned because of measurements obtained during the initial investigation of the nest site. All abandonments were due to either weather (i.e., summer hail), predators, or livestock. Viability and hatchability were unaffected for the remaining clutches that were measured during the field study. We found that candling and egg flotation are both viable methods for estimating hatch dates of bobwhite clutches during an initial measurement when a nest is discovered. When an entire clutch is measured accuracy can be within 1 day of the actual estimated hatch date (based on a 24-day incubation period). However, observers or researchers who will estimate hatch dates for clutches should be properly trained and allowed time to acclimate to the measuring techniques to potentially increase their accuracy at estimating hatch dates for northern bobwhite clutches

Evaluation of a Solar-Recharged Micro-GPS Datalogger for Northern Bobwhite in the Rolling Plains of Texas

The use of Global Positioning Systems (GPS) transmitters on northern bobwhite (Colinus virginianus; hereafter, bobwhite) could increase our understanding of fine-scale movements and habitat use for a declining game bird species. We evaluated solar-recharged micro-GPS dataloggers to determine the effectiveness of the units on free-ranging bobwhite and we conducted a controlled experiment to determine the accuracy of the dataloggers under a variety of canopy cover. We deployed the micro-GPS dataloggers on 25 bobwhites between August 2016 and April 2017 across 4 different ranches in the Rolling Plains of West Texas, USA. Accuracy (± standard error) for the 8 dataloggers across 3 trials for the stationary tests was 25.4 ± 3.8 m. Daily movement of bobwhite averaged 0.96 ± 0.09 km and morning movements averaged 0.49 ± 0.07 km. Average 95% and 50% minimum convex polygons for bobwhite area utilization were 15.2 ha and 3.6 ha, respectively. Our data indicate that solar-recharged micro-GPS dataloggers can be used to monitor bobwhites’ short-term fine-scale movements in West Texas

Genetic Structure of Northern Bobwhite in the Rolling Plains

The recent declines in northern bobwhite quail populations in the Rolling Plains of Texas have raised concerns about habitat connectivity and gene flow. In addition, bobwhites have several life history traits that make them likely to display high levels of spatial genetic structure including low survival, high reproductive rates, and low dispersal rates. To determine if populations within the Rolling Plains have limited gene flow, we investigated the genetic structure of northern bobwhites within the ecoregion. Blood samples were collected at 16 ranches, encompassing 22 million acres, between February 2010 and April 2013. Bobwhites were also samples at a ranch in South Texas to serve as an outgroup. Samples (n = 647) were genotyped at 14 microsatellite loci that averaged 19.00 ± 5.07 alleles per loci. Global Fst indicated significant genetic structure (p = 0.001) between ranches with no isolation by distance signal (p = 0.079). Program STRUCTURE, however, indicated many (n = 30) overlapping subpopulations with no ranch constituting a single subpopulation and individuals from the outgroup ranch were included in 11 subpopulations. It appears that bobwhites within the Rolling Plains have few restrictions to gene flow and dispersal is not limited by the dominant habitat, xeric rangeland. These results suggest that populations in the Rolling Plains are not in danger of becoming isolated nor are bottlenecks present due to the recent decline