Showing posts with label Environment. Show all posts
Showing posts with label Environment. Show all posts

Friday, April 10, 2020

The Number of Corona Virus Cases in Cambria County has Grown Exponentially While Health Behaviors Predict Cases in PA


The number of corona virus cases has grown exponentially in Cambria County.  I have been keeping track of the number of cases in a google sheet as can be seen above.  The cumulative case line has been following a cubic trend with the polynomial, y = 0.0347x2 - 3051.6x + 7E+07.  This equation accounts for 98.5% of the variability in the solid trend line.  

Two weeks ago I correlated the number of COVID-19 cases at the county level in Pennsylvania with the county health ranking for that county using Poisson regression.  This week I thought I would take a look at the submeasures for the rankings with the case and death numbers from April 8.  Population numbers for each county were added so that Philadelphia county could be added.

Number of Corona Cases

Corona Deaths 

Length of Life   Z-Score



Quality of Life Z-Score



Health Behavior Z-Score



Clinical Care   Z-Score



Social Economic   Z-Score



Physical Environment Z-Score



Number of Corona Cases



Corona Deaths 






The table above shows the univariate correlations of the submeasures with Philadelphia included.  For the number of cases, the quality of life z score (part of the health outcomes ranking) and the social economic z score (with the health factor ranking) were correlated.  For the number of deaths, quality of life, social economic, and physical environment (part of health factors) were correlated. Z scores are numbers scaled so that the mean is zero and 

For the case numbers, three of the county health ranking submeasures were significantly associated with the outcome along with population.  The poisson regression equation is given by:

ln(number of cases) = 4.15 -5.91*(health behavior z-score)  + 4.31*(social economic z score) - 0.74*(length of life z score) + 0.000002*(population)

This means that the number of cases increases as the health behavior and length of life z scores improve and (a negative score is better).  The number of cases decrease as the social economic z score improves.  Ln is the natural logarithm of the number of cases.

For the number of deaths in each county as of April 8, three submeasures were significantly associated with the number of cases.  The poisson regression equation is given by:

ln(number of deaths) = -0.14 - 7.97*(health behavior z-score) + 2.83*(social economic z score) + 1.62*(quality of life z score) + 0.000003*(population)

Like the number of cases, the natural logarithm of the predicted number of deaths at the county level increase as the health behavior z score decreases.  The predicted number of deaths decrease as the social economic, quality of life z scores, and population decrease.  

Adding multiple predictors often leads to variables that were not significant univariately to being significant in a multiple regression model, especially after population is adjusted for.  In the graphs above we see that Philadelphia county is an extreme outlier.  This is mostly due to its population.  Adding population to the model helps to negate its outlier effect.

These submeasures are themselves composites of dozens of county level statistics.  The next step is to look at these individual measures and the up to date counts of COVID-19 cases and deaths.

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Wednesday, April 10, 2013

Get the Lead Out

A new survey by the Centers for disease control or CDC suggests that about 500,000 children in the US have low blood lead levels (defined as 5 micrograms per deciliter) from 2007-2010.  This shows an 8.6% decrease compared to the last survey period in 1999-2002.  The graph at the left shows that there are higher percentages among african americans, the poor, and those who live in housing built before 1950.  

Many buildings built before 1950 still have paint that is lead based and have plumbing with lead pipes.  These paints were phased out but it is very expensive to replace and it is better in the long run just to build new housing to replace the paint.  The paint can flake off and when ingested by children can cause intellectual or developmental disabilities (the now politically correct term for mental retardation) and or learning disabilities.  

In the lab (on animal studies) and in correlational studies no dosage level of lead has been found that is completely benign on the brain.  It has a negative effect on the blood brain barrier which protects it from other toxins and has many other negative effects on intelligence test scores and brain function.  

The negative effects of lead exposure were recognized by Greek physicians as early as the 2nd century BC.  There is a theory that it contributed to the decline of the Roman Empire though that is controversial.   It was used heavily in the industrial revolution and in gasoline in the 1920s.  A way to test the theory would be to measure residual lead levels in the remains (teeth, bones, and if lucky hair) of the Roman citizens relative to those in the surrounding Barbarian tribes which sacked the empire from AD 410-476.  If the levels were higher in the Roman citizens it would support the theory.

It was phased out starting in 1978 in the US but the effects are still felt with leaded gasoline getting into the atmosphere through auto emissions, then into rain water, and finally the soil where it can remain for many years.  Other countries do not have as strict regulation on lead as the US does now.  


Episode 7 of Cosmos is devoted to lead poisoning and it's history with scientist Clair Patterson being voiced by Richard Gere. I can only embed the whole episode here while Hulu makes it available.

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Tuesday, May 10, 2011

Marcellus Shale Fracking

I haven't blogged a lot about environmental issues on CSI without Dead Bodies.  That's mostly because it's a topic I do not have a lot of experience with like I do with health care.  Most of my health care blogs have moved over to Healthcare 4 All PA.  That does not mean that those issues are not important.

Here in Pennsylvania and much of the eastern US, Marcellus shale drilling for natural gas using a process called fracking has become a hot topic with strong passions on both sides.  In fracking water and chemicals are pumped into a well and the natural gas bubbles up to the surface to be used.  It can be done in a variety of settings.  The chemicals used are a proprietary secret.  This burnoff was seen for miles at the Pittsburgh Mills shopping mall on January 8, 2011/

The documentary film Gasland, which was nominated for an Oscar this year, raises a lot of concerns about the fracking process.  In one dramatic scene it shows a man in Colorado setting fire to the well water from his kitchen faucet which has been contaminated by fracking.  Other health concerns are detailed in this film.

The industry has responded strongly to discredit Gasland.  I have heard geologists for Pennsylvania Department of Environmental Protection argue that the kind of contamination seen above can occur from natural processes.  There are many traditional gas wells which are not accounted for in the state.  Others such as T. Boone Pickens have stated that this process provides badly needed jobs for this part of the country and is safe.  Jon Stewart doesn't really challenge him in this clip.
For those who are unfamiliar with the process it is often hard to know who is correct.  The website FracTracker is a source of data for analysis on this topic.  I will be looking at it to learn more about the pros and cons.  No one really knows what the long term implications are.  To give this topic a fair analysis it's best for me not to make any assumptions as I analyze the data.


I was just informed of another post from the Open Knowledge Foundation about how to track lobbyists work.  The gas industry, environmental activists, the health care industry and just about everyone else is engaged in this activity.  This could be helpful in a lot of investigations.

How to study lobbying with crowdsourced open data

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