Shane Granger has an excellent new post on his Random Analytics blog: H7N9 Age Pyramid and Average Age (to 22 Jan 2014). Click through for the full post. After discussing Dr. Ian Mackay's H7N9 graphics, Shane continues:
I’m quite an admirer of Ian’s work, especially those graphs looking at accumulation/epidemiological data. I couldn’t help but notice that his Age Band chart uses a standard 2D column graph rather than a 2-way bar graph as used by demographers. I thought the use of that methodology along with a graph showing the decline in average age since October 2013 might be a better illustration of his very sound reasoning.
So, to add emphasis to Ian’s article I spent last night updating my H7N9 data, untouched since early December and did a couple of new graphs up to and including case number #216 (sourced from FluTrackers).
The first graph is an age pyramid (otherwise known as a beehive graph) commonly used by demographers and health experts to map population and mortality distributions. As you can see by using this methodology I’ve been able to bring the population groupings to just 5-year intervals which highlights the continued concentration of male onsets (70.2%). Of interest also are the aged cohorts with the highest percentile of cases with 55 – 59 (21-male/5-female/12.1%), 65-69 (19-male/5-female/11.2%) and 50-54 (13-male/10-female/10.7%). These three groups alone make up more than a third of all H7N9 onsets to date.
The second chart shows the average age of all onsets since case number #2 through to case number #216 (minus one case which does not come with age data). Interestingly, the first two victims were aged 87 and 27, thus the average age from those two was 57 which is in the variable range of the virus through its entire 11-month history.
As you can see from the coloured section which represents all onsets from October 2013 (effectively, the second wave of H7N9) the average (or mean) age has reduced by approximately two-years. According to my data, the average age for onsets for wave 1 was 57.0 while currently for wave 2 it sits at 52.7.