Cancer is in the news. NBC News recently reported on a cohort study that has dire implications for Millennials and Generation X. The prevalence of 17 different cancers is notably higher in these younger generations. I have noted here that during the 20th century, American life expectancy marched upward. That has seemingly paused or ceased. See Life Expectancy Changes (November 2016) and Life Expectancy and Risks (September 2022). Life expectancy is simply not increasing in America presently.
The list of 17 cancers is not surprising. It includes several that we have come to accept as serious societal challenges. A variety of cancers and other health threats have seen medical advances, decreasing frequency, and significant progress. Witnessing the resurgence of these cancers is at best disappointing. There is significant curiosity as to both the numerical resurgence and the propensity among younger people.
It is fair to say that some portion of the news is essentially “what is so.” That is, the numbers are increasing. The next question, the more important question, is why. The trend is to look at lifestyle habits. One that is leading, the discussions is obesity, which has been discussed in terms of a multitude of health issues, risks, and challenges.
Is obesity sufficient to produce the kinds of results reported in terms of diagnosis increases, and mortality? Well, the news article conveys some spirit of consensus as to obesity. It seems fair to conclude that some see this as a major causative factor. There’s also the suggestion of other factorial causes, their analysis, consideration, and discussion.
Over the course of decades, in the world of injury and occupational disease, I have spent a reasonable amount of time studying medicine. I have had many renowned physicians explain to me that causation can be a difficult analysis in any event. They have described to me, the amazing complexity of the human body, the variety of systems, the interdependence and inter-relationships, and the resulting challenges in ever pointing at a particular cause or any outcome. I have been so blessed by their tutelage, patience, and indulgence.
We must perhaps be cautious of Occam‘s razor analysis when dealing with something so complex. Occam instructed us that generally, the simplest solution is the correct one. Thus, Occam would likely point at obesity, dietary changes, food, insecurity, or untoward results of other scientific advancements (antibiotics are mentioned in the article). Occam, however, likely did not have access to the depth of knowledge that will undoubtedly be thrown at these cancer increase hypotheses.
Another report, nearly coincidental, brought to my attention conclusions that your cancer risk can be diminished through lifestyle choices. Everyone living above ground has long understood the conclusion that smoking is a health risk. Despite that, some still believe “it depends.“ ABC News reports that perhaps 40% of cancer risk and more like half the fatality rate could be prevented by choices we make.
This second recent study informs that lifestyle choices have been shown to diminish cancer risk across cohorts of patients. Those specifically mentioned focus on smoking, alcohol use, and obesity. In this, some may see congruency with the discussion above. Obesity, perhaps, is the enemy.
Many scientists have described to me, the challenges of correlation versus causality. Perhaps the most brilliant of these simply directed me to look those two words up in my medical dictionary. The points of the correlation versus causality distinction focus on the fact that there may be a multitude of findings that are of interest in any analysis.
Correlation is a "state of being related," according to Webster. Two things can change in tandem without one being the cause (or a cause) of the other.
For example, a patient may contract a disease process after visiting a particular locality ("Bigville," a fictional community). Standing alone, that is a correlation, not causation.
But what if a million people contract that disease after visiting Bigville? Is that coincidence or does it indicate causation?
Some might say it depends on whether everyone who visited Bigville was diagnosed. Is the frequency of cancer among Bigville visitors 100%?
And, we might consider the frequency rate among Bigville visitors compared to the frequency rate of the disease generally. If the 1 million represents one in ten of the Bigville visitors, is that consistent with those who do not visit Bigville? If one in ten of non-visitors is similarly diagnosed, then the "1 million" statistic may be less persuasive.
The fact that 1 million Bigville visitors are diagnosed is not, alone, the proof of causation that might be sought. It may be correlation. Or, if the rate of diagnosis is no greater proportionally in Bigville visitors, it may be merely coincidence.
In that context, one may wonder if is it obesity that is a risk in the current analysis. Alternatively, could it be that things that cause obesity may correlate to the onset of certain disease processes? Perhaps it is not “that“ I am fat, but “why“ I am fat?
Is it the type of food or diet I consume? Might what I consume contribute to my being obese? Is it possible that those same foods or food groups might also favor or cause some forms of cancer?
Is the culprit my (in)activity level? Might my sedentary lifestyle and love of relaxation cause my body weight to increase? Is it possible that a second effect of that in(activity) level might be the prevalence of cancer onset?
Thus, there are chances for establishing causation: obesity causes cancer (causation). And, there is the chance that (in)activity causes obesity and cancer (correlation).
Why is there this increase in the younger generations? Certainly, there is a recognized disparity. Younger people are seeing increased diagnosis. But why? Is it evolutionary, environmental, or behavioral? We recognize there is a disparity, but why? Have they adopted different lifestyle choices in terms of diet, exercise, or otherwise? Or is there some other causative factor(s) that are coincident (correlated) with an independent increase in cancer diagnosis and death?
This is often the analysis that experts debate in workers' compensation, whether as to accident or disease. If a patient has disease "a" or injury "b," the causation question is paramount. Did that arise out of employment? Is work the cause of the injury/illness or is work a coincidence? In the disease category, such questions have become definitional in various statutes (excluding "ordinary diseases of life"). But, in accident cases, in various jurisdictions, the burden is there for a patient to prove that some work event or action "caused" injury "b" (causation) not merely to prove that symptoms were first experienced at work (correlation).
As the brilliant brains attack the untoward recent increase in cancer, diagnosis, and mortality, it will be intriguing for the rest of us to watch. In the meantime, however, it would seem sound at least to follow the possible conclusions. Whatever the causative connection, if any, there is a correlation between tobacco, alcohol, diet, and exercise. Your health can potentially be improved, and your risk of cancer diminished, through behavior. I am not saying act like a Boomer, but there could be merit in our "old guy" habits.
It would be absurd to conclude that the discussed behaviors are the only culprits. Each of us has likely known a fit, sober, non-smoker, who was stricken unexpectedly with cancer. In the end, there are likely many contributing potential causes for those diseases and heredity is likely at the top of the list. Nonetheless, anything one can do to diminish probabilities seems advisable.
The correlation has been deemed strong, and frankly, life is too short to ignore it.