Heart Disease Epidemic and Latitude Effect: Reconciliation

For the last half century, heart disease has been the most common cause of death in rich countries — more common than cancer, for example. I recently discussed the observation of David Grimes, a British gastroenterologist, that heart disease has followed an infectious-disease epidemic-like pattern: sharp rise, sharp fall. From 1920 to 1970, heart disease in England ¬†increased by a factor of maybe 100; from a very low level to 500 deaths per 100,000 people per year. From 1970 to 2010, it has decreased by a factor of 10. This pattern cannot be explained by any popular idea about heart disease. For example, dietary or exercise or activity changes cannot explain it. They haven’t changed the right way (way up, way down) at the right time (peaking in 1970). In spite of this ignorance, I have never heard a health expert express doubt about what causes heart disease. This fits with what I learned when I studied myself. What I learned had little correlation with what experts said.

Before the epidemic paper, Grimes wrote a book about heart disease. It stressed the importance of latitude: heart disease is more common at more extreme latitudes. For example, it is more common in Scotland than the south of England. The same correlation can be seen in many data sets and with other diseases, including influenza, variant Creuztfeldt-Jacob disease, multiple sclerosis, Crohn’s disease¬†and other digestive diseases. More extreme latitudes get less sun. Grimes took the importance of latitude to suggest the importance of Vitamin D. Better sleep with more sun is another possible explanation.

The amount of sunlight has changed very little over the last hundred years so it cannot explain the epidemic-like rise and fall of heart disease. I asked Grimes how he reconciled the two sets of findings. He replied:

It took twenty years for me to realize the importance of the sun. I always felt that diet was grossly exaggerated and that victim-blaming was politically and medically convenient – disease was due to the sufferers and it was really up to them to correct their delinquent life-styles. I was brought up and work in the north-west of England, close to Manchester. The population has the shortest life-expectancy in England, Scotland and Northern Ireland even worse. It must be a climate effect. And so on to sunlight. So many parallels from a variety of diseases.

When I wrote my book I was aware of the unexplained decline of CHD deaths and I suggested that the UK Clean Air Act of 1953 might have been the turning point, the effect being after 1970. Cleaning of the air did increase sun exposure but the decline of CHD deaths since 1970 has been so great that there must be more to it than clean air and more sun. At that time I was unaware of the rise of CHD deaths after 1924 and so I was unaware of the obvious epidemic. I now realize that CHD must have been due to an environmental factor, probably biological, and unidentified micro-organism. This is the cause, but the sun, through immune-enhancement, controls the distribution, geographical, social and ethnic. The same applies to many cancers, multiple sclerosis, Crohn’s disease (my main area of clinical activity), and several others. I think this reconciles the sun and a biological epidemic.

He has written three related ebooks: Vitamin D: Evolution and Action, Vitamin D: What It Can Do For Your Baby, and You Will Not Die of a Heart Attack.

9 Responses to “Heart Disease Epidemic and Latitude Effect: Reconciliation”

  1. LemmusLemmus Says:

    Interesting. If I may go OT, do you have any thoughts on this:

    http://well.blogs.nytimes.com/2013/06/27/how-carbs-can-trigger-food-cravings/?_r=0

  2. Three Pipe Problem Says:

    What is your basis for saying that sunlight has not changed much. Have you ever heard of those who claim “Global Dimming” has been substantial based on long-running “pan evaporation” experiments?

    Seth: My basis is what I have read about global weather during the 20th century. Sunlight changes can’t possibly explain the results Grimes describes (the rise and fall of heart disease by a factor of 10-100, peaking at 1970). I did not know about that Global Dimming stuff, it sounds interesting.

  3. Three Pipe Problem Says:

    Glancing at the wiki it looks like it has also reversed recently.

    Seth: Global Dimming, at 4% or less, cannot explain changes by a factor of 10.

  4. Sam Says:

    Did you happen to ask Grimes about the effect of smoking on CHD? It seems odd that he apparently disregards tobacco use entirely, given that it is known to be a significant risk factor for heart disease, and that tobacco consumption has varied significantly over time. I’m not saying that Vitamin D doesn’t matter, or anything like that, but just that you’d expect to see some discussion of the impact of tobacco.

    Here’s a link to some historical stats on UK tobacco consumption, which peaked in 1945:
    http://www.cancerresearchuk.org/cancer-info/cancerstats/types/lung/smoking/lung-cancer-and-smoking-statistics#history

    Seth: No, I didn’t ask him.

  5. Tom Says:

    I just read his book “You Will Not Die of A Heart Attack.” It’s terrific, and I’m sure my GP (and most cardiologists, for that matter) have no idea about the facts laid out in it.

    It’s worth the money for the Deaths from CHD chart alone.

  6. Sam Says:

    Sorry for the double comment, but this paper from BMC Public Health also shows a much less dramatic drop in CHD mortality than Grimes’s paper appears to – in part due to the way the data are presented. For the age groups at the greatest risk of CHD, the decline from 1970 to today is more like 50%, rather than 95% (or a factor of 10).

    http://www.biomedcentral.com/1471-2458/8/148/figure/F1?highres=y
    http://www.biomedcentral.com/1471-2458/8/148/

  7. Tom Says:

    Interesting. I’d love to know what Dr. Grimes has to say about the discrepancy.

  8. dearieme Says:

    Don’t put too much weight on the Clean Air Act. According to the enviro writer Lomberg, if you plot the decline of dirt in the air in the UK (or maybe England and Wales) there is no change of slope when the Act came into force. [I have not checked this claim.]

    On the other hand, there is no doubt that the air got cleaner and cleaner whatever the actual cause. And anyway, maybe the slope would have changed for the worse but for the Act. For example, maybe economics drove industries to replace coal by oil but it needed the Act to force domestic users off coal.

  9. JM Says:

    I also found his ebook, “You will not die of a heart attack” interesting reading, although it appears to be just a version of his article that was also linked to here (which you can get for free). He doesn’t really solve the mystery of what caused this epidemic but does shed a new light on something everyone seems to think they know they cause of. Also, it isn’t as close to an end as he implies – I know of two men in their 50′s who suffered recent heart attacks, and in neither case was there a clear case of obvious cause. The doctor’s just shrugged their shoulders or said their must have been an unknown family history when questioned – so frustrating!