The term ‘hepatitis’
The term Hepatitis is not referring to a specific disease or virus but generally refers to an inflammation of the liver (greek ‘hepar’). Responsible for such a condition can be viruses (not just the ones referred to as Hepatitis A to E), poisoning or mechanic traumas. In this article I am referring to viral hepatitis.
Statistics on causes of death for Germany in general
Randomly pivoting through the statistics on causes of death in Germany (published by the Federal Bureau of Statistics on their online platform GENESIS) I was searching for obvious anomalies in the data. And indeed only few causes display a simple trend or at least some steadiness at all. Most of the charts for fatatlities against time look very similar to the Alps or the skyline of some random fast growing chinese metropole region. It became pretty clear that for interpreting most of the ups and downs and their relations a close look on the nature of the underlying fatality and its context would be required.
A sudden increase of deaths caused by viral Hepatitis in 1998 for all age groups
Having said that – let’s have a look at the development of fatalities caused by viral hepatits for different age groups.
I chose four age groups to give more insight to how viral hepatits affects society. Oviously something happened in 1998, as all chosen age groups report increases of deaths ranging from 85% to 227%. It is also obvious that the death counts of all age groups are still (2010) affected by this increase more than a decade ago!
But of course the age distribution of our population is also changing over time. So I took offical statistics on Germany’s population and calculated the rate of deaths over time.
Now first of all, if you look at this chart the situation certainly looks less dramatic given that of all persons aged below 70 years less than a percent of a percent is dying of a viral hepatits – I certainly don’t intend to cause panic!
Death rate trends for different age groups
Another aspect I find very thought provoking is the different trend of death rates for the age groups 70 to 79 and 80 years to infinity. A reason might be that people above 80 are often living in retirement homes where hepatitis is passed from one inhabitant to the next very easily. That would explain why this age group is the only one showing a clear upswing. But of course 80-inf is also the only age group you can’t escape alive anyway. People aged from 70 to 79 years might catch viral hepatits and die aged 80 or later from it.
What caused the increase?
What happened in 1997/98 remains a mystery. A google search for “hepatitis outbreak 1997” leads to articles about an outbreak of Hepatitis A in the States caused by frozen strawberries originating in Mexico in 1997. According to the wikipedia article on Hepatitis A fatalities due to this virus are rather rare – but relatively high for persons above 50 years and relatively very low for children.
As you can see from the chart, the age group for 0 to 19 years has not been significantly affected by whatever caused the increase in 1998 for the other age groups. This might speak for a link with the Hepatitis A outbreak in the USA.
What do the experts know about it?
I already wrote a question regarding this observation to three high profile medical professors (from Katholische Klinik Oberhausen and Charité) specialized on diseases of the liver and the Robert Koch institute. Unfortunately none of them could tell me more about this increase. The RKI at least sent me a link to their quarterly bulletin on contagious diseases from 1998. But the figures there just show no significant increases at all.
(original article published on www.joyofdata.de)
Hello again :)!
I have noticed this interesting post the first time I visited your site a couple of days ago. It is quite intriguing and I was planning to comment on it, once I got the chance to do a bit of online searching. Searching done, I have a couple of ideas, but mind you, these are just my personal ideas, approximations or guesstimates. I might be completly wrong, but here it goes. Nobody should take this as definitve argument!
To begin with, I’d like to make a few points:
1. Once the increase started, it can be observed that it has maintained at high levels to the present day.
2. The viral hepatitis family got a new member recognized ( of course, the member was always there, but science just didn’t discover him) in 1989: hepatitis C virus. Acute infection with hep C virus is not very turbulent and might easily go undetected. Once the chronic infection stage sets in, it might take a decade or more to produce serious side effects like liver failure, cirrhosis, etc.
3. The increase is only observed in older people. Kids are almost untouched, youngsters and youg adults are almost untouched. The kind of people that are generally healthies and require little to no invasive medical procedure (this is an important point!)
4. Hep C is very different from hepA. Taxonomically, these viruses are worlds appart.Hep A virus very rarely causes fatality and never generates chronic infection. Hep C determines mild symptoms during the acute phase, but almost always generates a chronic infection that damages the liver across many years (even decades) leading through death not through hepatitis itself, but through the consequences of long-term liver inflamation. (this might be getting to technical so I won’t go any further. More good information on wikipedia)
I hope I will manage to lay down a clear text ( altough I do have the unfortunate tendency to be verbose). Here goes nothing:
I read ( or rather tried to) the contagious disease bulletin from 1998 and it does have a graph on the first page that shows a slight increase of “other” forms of hepatitis and it goes on to explain in the text that those cases are mostly hepatitis C (page 123), I think… – es tut mir leid, aber meine Deutsch is schelechter mit jeden Jahre ohne Ubung.
And this is the crux of the matter in my opinion: there have been numerous cases of iatrogenic infections with hepatitis C virus. That means infections given to patients while they were receiving other types of care. Now, hepC virus is not the most contagious of the bunch ( hep A and B are much more contagious and easily spread). Hepatitis C tends to spread via direct contact with infectious material, for example improper sterilization of medical instruments/devices and blood transfusions and intravenous drug use. Sexual contact is also a means of transmiting the virus, yet some researchers say that it might not be easy or even common for this to happen. Anyway, details…
One cannot blame the medical staff for the transfusions part, since not knowing what the hep C virus was there was no way of testing donors for it. But as medicine progresed hugely during the second part of the XXth century quite alot of people might have gotten the infection after dental procedures,improper hygine at dialysis machines, endoscopy, heart surgery that required transfusion, etc. This is another crucial point. The vast majority of people that require extensive dental work, colonoscopies, dialysis, heart surgery+tranfusion and so forth are way more likely to be past middle age. This is consistent with your graphs that show a severe affliction in older cohorts. The older one is, the higher the chance that they encoutered the virus during medical procedures or through intercourse. The minor fact the the 80+ years cohort seems to do better than the others is the fact that fewer people live to be 80+ years-old. Other things get to them, before the virus becomes clinically manifest.
Also, I have found some cases, in Germany and Ireland of large number of women getting the infection after a vaccine.The vaccine was obtained from a living donor who was otherswise healthy. Romania had similar problems with tainted biological material during late ’80-early ’90. These were widespread problems in many countries, caused by the fact that not knowing about something means you can’t test pacients for it (modern examples include de hepatitis G virus and the TT virus). I won’t go into detail about this vaccine, it is thorougly explained in the articles. I just want to say that those accidents could never happen today since the technology for making such vaccines is different and extremely safe. Anti-vax campaigners should not take this as an oportunity to bash vaccines. Vaccines ARE GOOD!
In any case, those women got the virus and furthermore, some might even have transmitted it along through intercourse.
There is also one more issue: intravenous drug abuse. Hepatitis C is extremly easily transmitted via tainted needles, analogous to poorly sterilized medical devices or tainted blood.
And now, for the final issue. WHY has the incidence of hepatitis risen so dramatically and stayed at such high levels in the older cohorts?
Well, since the discovery in 1989 of the hepC virus it took a few years to mass-produce reliable, diagnostic testing kits. Once a country would get enough of these kits there is the problem of actually testing the population and gathering the data. Also, once the problem is recognized, at risk groups of people -such a those who needed tranfusions and iv drug users- needed to be tested systematically. This might add at least another year of delay until reliable official data is produced. If the health services did wide-spread screening for hepC, they also did widespread screenig for hepB at the same point (it makes alot of financial sense to do so). Thus, alot of cases were officialy registered for the first time during those screenings, either with hep B or C.
Now, out of the 3 major types of hepatitis, hep C is the rarest. Why such huge increases? Well, as we take a look the graph, the increase is not actually that huge in terms of real life numbers. It just seems large when you take them into account as percentages. Also, as you pointed out, less than 0.01% of deaths are caused by this problem in the elderly.
Also, the mid ’90 were a paradigm shift in terms of diagnosing and counting liver disease for statistics. Ever more powerful diagnostic tool kits were (and still are) being developed that could detect various stages of the infection.
So, that’s my take on the how and why of this curious conundrum. A combination of the accumulation over time of an infection with a previously unknown agent and the redesigning of the way these diseases are diagnosed, monitored and take into count.
That’s about it, I hope this all makes sence!
Auf wiedersehen!
Alex
Alex – if you ever happen to visit Munich, I have to invite you to a coffee – you earned it!
I think …
2. The viral hepatitis family got a new member recognized ( of course, the member was always there, but science just didn’t discover him) in1989: hepatitis C virus. Acute infection with hep C virus is not very turbulent and might easily go undetected. Once the chronic infection stage sets in, it might take a decade or more to produce serious side effects like liver failure, cirrhosis, etc.
… together with …
Also, the mid ’90 were a paradigm shift in terms of diagnosing and counting liver disease for statistics. Ever more powerful diagnostic tool kits were (and still are) being developed that could detect various stages of the infection.
… formes a reasonable explanation – Good job!
Not very relevant – just noticed it …
The minor fact the the 80+ years cohort seems to do better than the others is the fact that fewer people live to be 80+ years-old. Other things get to them, before the virus becomes clinically manifest.
For relative numbers – which I think are most relevant for interpretation – the 80+ cohort is doing worst.
Now, out of the 3 major types of hepatitis, hep C is the rarest. Why such huge increases? Well, as we take a look the graph, the increase is not actually that huge in terms of real life numbers. It just seems large when you take them into account as percentages. Also, as you pointed out, less than 0.01% of deaths are caused by this problem in the elderly.
I beg to differ in this case b/c if you take the stability of the post-increase trend (for relative death toll) into account and compare the variation around the trend with the magnitude of the sudden increase then the increase can be considered as being highly statistically significant. I understand you don’t doubt this – I just want to clarify that even if the relevancy of this observation for society might be minute, the observation by itself is revealing a clear pattern.
Given your authorial passion and technical expertise you are most welcome to write a guest article on some datalicious subject. I would be honoured!
Cheers
Raffael
Hello! and thanks for the coffee :D
In regards to the 80+ years group, I was referring to the chart in absolute numbers. Indeed, the relative numbers chart shows they are doing worst.
But some people might have read this part
and then look at the absolute numbers and say that I was wrong, because the 80+ group was didn’t have the highest number of fatalities. BUt the other graph shows the true intensity of the problem.
I was trying to be a bit clearer, but my verbosity got the best of me :D.
I’d like to get the chance to discuss some “datalicious subjects” with you and others that might be interested but sadly I’m entering one of my busiest years yet, with all the finishing med school and speacialty exams and all that, but. BUT!, if and when I stumble across something interesting maybe we could talk about turning it into a post.
I’m doing (or rather trying to do) some work on autism spectrum disorders, but money for research is really tight here. ‘Nuff said! If the data proves to be interesting, we could talk about that data; or something relating to public health. If ASDs are my “stable relationship”, then public healht recently turned out to be my “crush”. :D
I’m really glad we got a chance to talk about datalicious subjects, it is quite refreshing and fun!
Have a great day!
Alex
BUT!, if and when I stumble across something interesting maybe we could talk about turning it into a post.
Deal!
Have a great day!
I second that!
Cheers
Raffael