[ed. note: Michael Jorrin, who I call Doc Gumshoe, is a longtime medical writer (not a doctor) who writes for us about medicine and health a couple times a month. He has agreed to our trading and disclosure restrictions, but does not generally write directly about investment ideas. His ideas, thoughts and words are his own, and you can see all his past pieces here.]
As with tidings in general, some are glad and some are not so glad. Let’s start out with one that’s definitely on the glad side of the ledger.
To wit: the incidence of type 2 diabetes is declining. Let me say that again. New cases of type 2 diabetes, the kind that was formerly called “adult-onset diabetes,” but has recently been reported to a troubling extent in teen-agers and even children, are occurring less frequently.
Here are some data.
- In adults of ages from 18 to 44:
- Between 1980 and 1987, the incidence was under 2 cases per 1,000 population.
- Between 1987 and 2009, the incidence increased to 4.3 cases per 1,000.
- Between 2009 and 2014, the incidence decreased to 3.3 cases per 1,000.
- In adults of ages from 45 to 64:
- Between 1980 and 1999, the incidence increased from 5.2 to 8.9 cases per 1,000.
- Between 1999 and 2008, the incidence increased to 14.3 cases per 1,000.
- Between 2008 and 2014, the incidence decreased to 10.5 cases per 1,000.
- In adults of ages from 65 to 79:
- Between 1980 and 1991, the incidence increased from 6.9 to 8.9 cases per 1,000.
- Between 1991 and 2003, the incidence increased from 8.9 to 14.3 cases per 1,000.
- Between 2003 and 2014, the incidence decreased to 12.1 cases per 1,000.
As you can see, the largest decrease was in what we might call “middle-aged” adults, although younger adults experienced a similar percentage decrease, and in older adults, the decrease began a few years earlier. These encouraging decreases have to be regarded in the light of the large and problematic increases over the longer span from 1980 to the present, and, of course, it’s hard to predict whether the decreases will continue. When the first Doc Gumshoe blog about diabetes appeared, back in June of 2014, I cited the prediction that if present trends continued, about one-third of US adults would be diabetic by mid-century, and those proportions might be higher in groups such as Hispanics, African-Americans, and American Indian and Alaskan Natives, where the prevalence is already considerably higher than in the US population in general.
The numbers I quoted above, about the decrease in incidence, are from the CDC National Center for Health Statistics, and although they were no doubt available earlier if I had diligently sleuthed, I think they were reluctant to put them out too prominently, lest they be accused of making too much of what might turn out to be a blip.
I also pointed out in that piece that we’re far from the most affected country, In China, the incidence of diabetes has increased from less than 1% in 1980 to 12% at present. It’s also estimated that half of the entire Chinese population are prediabetic, and that by mid-century fully 40% of the population will be diabetic.
But to return to the excellent news about the decrease in the incidence here in our own country, why might this be? The CDC isn’t publicly venturing an opinion, but here’s some statistics that provide at least a tempting association.
The per capita consumption of soft drinks in the US has dropped from 53 gallons in 2000 to 43.8 gallons in 2014. In percentage terms, that’s similar to the decrease in new cases of type 2 diabetes in the past ten years or so. Americans have been switching from soft drinks to bottled water, consumption of which has been on a rapid increase. (Speaking for himself, Doc Gumshoe remains an advocate of tap water, which comes from our own excellent well!)
Why might this association be considered causal? Many experts in diabetes consider sugary soft drinks to be particularly harmful in bringing about diabetes. That’s because these drinks evade the kind of insulin response that normally takes place when we eat bona fide food. I discussed this in some detail in the diabetes blogs last year, but the quick version is that our insulin response is bi-phasic. The basal insulin secretion goes on all the time, keeping blood glucose at more or less normal levels and helping cells metabolize glucose for energy. The prandial insulin response starts fairly quickly, about 15 minutes after food enters the digestive system. What happens is that molecules called incretins signal the pancreatic beta cells to release insulin, so that by the time glucose from that meal starts to enter the blood-stream, insulin is ready to do its job. But glucose from soft drinks starts getting into the blood before the soft drink gets into the digestive system, so blood glucose goes to very high levels. This in turn triggers the release of abnormally high levels of insulin. And those high insulin levels lead to resistance at the insulin receptors, which is the first step on the way to type 2 diabetes.
In short, the big can of soda pop is a whole lot worse than the big slice of apple pie.
Of course, the decline in new diabetes cases doesn’t bring it back to the level it was before the whole country went on the junk food binge, and it certainly seems as though a lot of the world is on a similar binge. But maybe we’re headed in the right direction.
Next, some good news tempered with some bad news
First, let’s put this in the context of the overall good news: According to the Centers for Disease Control, the U.S. death rate for all causes declined 43% between 1969 and 2013, from about 1,279 per 100,000 people to about 730. This was due to large decreases in the deaths due to heart disease, stroke, and cancer.
However, one group of our fellow Americans did not share in this good news. And it was not, as some of us might expect, underprivileged minorities. African-Americans and Hispanics experienced improvements in life expectancy.
The group that did not see an improvement in life expectancy was white middle-aged Americans with less than a college education. Not only did their life expectancy not increase, it declined substantially. Life spans for most Americans and for residents of most developed countries have continued to improve at the rate of about 2% per year, as death rates declined. Starting in 1990, the number of deaths per 100,000 population in France, Germany, the UK, Canada, Australia, and Sweden declined from a range of 350 to 450 to a range of 100 to 300 by 2013. This decline in the death rate was also the case for Hispanics in the US, whose overall death rate was lower than that of US whites. But the death rate for middle-aged US whites actually increased by 134 per 100,000 population, to about 425 per 100,000 population.
This increase in the death rate and decline in the life expectancy of US whites was mostly due to higher mortality in that group of white Americans age 45 to 54 who had not attended college. During the years when the life expectancy of every other cohort in the US was increasing, theirs was shrinking at the rate of about one-half percent per year. This increase in the death rate did not apply to US whites older than 65 years, but was limited to whites in their middle years.
Among the counter-intuitive consequences of this trend is that as a group, American women in that demographic now have a life-expectancy about five years shorter than their mothers.
Angus Deaton, one of the authors of the study (Proc Natl Acad Sci 12/8/2015) reporting this deeply troubling trend, pointed