Statistical inferences vs. biological realities

A 2019 UCLA study introduced a derivative of the epigenetic clock named GrimAge:

“DNAm GrimAge, a linear combination of chronological age, sex, and DNAm-based surrogate biomarkers for seven plasma proteins and smoking pack-years, outperforms all other DNAm-based biomarkers, on a variety of health-related metrics.

An age-adjusted version of DNAm GrimAge, which can be regarded as a new measure of epigenetic age acceleration (AgeAccelGrim), is associated with a host of age-related conditions, lifestyle factors, and clinical biomarkers. Using large scale validation data from three ethnic groups, we demonstrate that AgeAccelGrim stands out among pre-existing epigenetic clocks in terms of its predictive ability for time-to-death, time-to-coronary heart disease, time-to-cancer, its association with computed tomography data for fatty liver/excess fat, and early age at menopause.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6366976/ “DNA methylation GrimAge strongly predicts lifespan and healthspan”


A miserable attempt at reporting the study’s findings included angles of superstition, fear-of-the-future, and suspicion-by-spurious-association:

“The research has already captured the attention of the life insurance industry. After all, a solid death date could mean real savings when it comes to pricing policies.

The hope is that if and when legitimate anti-aging drugs are developed, GrimAge could be used to test their effectiveness. In a world with functional anti-aging drugs, “doctors could test [your GrimAge number] and say, ‘You know what, you’re aging too quickly. Take this,'” Horvath said.”

https://onezero.medium.com/a-new-test-predicts-when-youll-die-give-or-take-a-few-years-2d08147c8ea6 “A New Test Predicts When You’ll Die (Give or Take a Few Years)”


A detailed blog post from Josh Mitteldorf provided scientific coverage of the study:

“Methylation sites associated with smoking history predicted how long the person would live more accurately than the smoking history itself. Even stranger, the methylation marks most closely associated with smoking were found to be a powerful indication of future health even when the sample was confined to non-smokers.

The DNAm GrimAge clock was developed in two stages, a correlation of a correlation. Curiously, the indirect computation yields the better result.

Horvath’s finding that secondary methylation indicators are more accurate than the underlying primary indicator from which they were derived is provocative, and calls out for a new understanding.”

https://joshmitteldorf.scienceblog.com/2019/03/05/dnam-grimage-the-newest-methylation-clock “DNAm GrimAge—the Newest Methylation Clock”


When there are logical disconnects in findings like the above, it’s time to examine underlying premises. As noted in Group statistics don’t necessarily describe an individual, an assumption required by statistical analyses is that each measured item in the sample is interchangeable with the next.

This presumption is often false, producing individually inapplicable results. For example, the review from earlier this week Immune memory vs. immune adaptation included this description of the adaptive immune system:

“To be effective, highly specific immune response requires huge diversity of receptors and antibodies, which is achieved by somatic rearrangement of gene segments. Recombination results in millions of TCR [T cell receptor] and antibody variants able to recognize and neutralize millions of various antigens.”

Standard statistics of millions of T cell receptor and antibody variants won’t represent their individually unique properties. Individual differences are their purpose and benefit to us.

The GrimAge study’s overreach was most apparent in stratifying educational attainment to develop correlations. As mentioned in Does a societal mandate cause DNA methylation? such statistics are poor evidence of each individual’s biological realities.

Neither derivatives of group statistics, nor correlations of correlations, seem to be the techniques needed to understand biological causes of effects. Commentators on the GrimAge study alluded to this point, but glossed it over:

“It remains a mystery why exactly the epigenetic clocks work, and whether age-related changes in DNA methylation contribute to the cause of aging or are a result of it.”

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Immune memory vs. immune adaptation

This 2019 Dutch/German/Romanian perspective aimed for a better understanding of immune systems:

“Based on molecular, immunological, and evolutionary arguments, we propose that innate immune memory is a primitive form of immune memory present in all living organisms, while adaptive immune memory is an advanced form of immune memory representing an evolutionary innovation in vertebrates.

Innate immune responses have the capacity to be trained and thereby exert a new type of immunological memory upon reinfection. The central feature of trained innate immune cells is the ability to mount a qualitatively and quantitatively different transcriptional response when challenged with microbes or danger signals. Evidence supports the convergence of multiple regulatory layers for mediating innate immune memory, including changes in chromatin organization, DNA methylation, and probably non-coding RNAs such as microRNAs and/or long non-coding RNAs.

Two properties of the adaptive immune response are mediated by two fundamentally different types of mechanisms:

  1. The higher magnitude and speed of the response is mediated by epigenetic programming.
  2. The specificity of the response is insured by gene recombination of TCR [T cell receptor] and BCR [B cell receptor] and clonal expansion of specific cell subpopulations upon antigen recognition.

To be effective, highly specific immune response requires huge diversity of receptors and antibodies, which is achieved by somatic rearrangement of gene segments. Recombination results in millions of TCR and antibody variants able to recognize and neutralize millions of various antigens.”


The paper included speculations such as the “Evidence supports..probably non-coding RNAs” quoted above, and the penultimate sentence:

“One can envision that vaccines that are capable of inducing both forms of immune memory at the same time would be more effective.”

100% factual evidence is preferred. The paper’s overall information can only be as accurate as the paper’s least accurate information.

The lead author coauthored A dietary supplement that trains the innate immune system and a study referenced in Eat your oats.

https://www.sciencedirect.com/science/article/pii/S1931312818306334 “Innate and Adaptive Immune Memory: an Evolutionary Continuum in the Host’s Response to Pathogens” (not freely available)

Our brains are shaped by our early environments

This 2019 McGill paper reviewed human and animal studies on brain-shaping influences from the fetal period through childhood:

“In neonates, regions of the methylome that are highly variable across individuals are explained by the genotype alone in 25 percent of cases. The best explanation for 75 percent of variably methylated regions is the interaction of genotype with different in utero environments.

A meta-analysis including 45,821 individuals with attention-deficit/hyperactivity disorder and 9,207,363 controls suggests that conditions such as preeclampsia, Apgar score lower than 7 at 5 minutes, breech/transverse presentations, and prolapsed/nuchal cord – all of which involve some sort of poor oxygenation during delivery – are significantly associated with attention-deficit/hyperactivity disorder. The dopaminergic system seems to be one of the brain systems most affected by perinatal hypoxia-ischemia.

Exposure to childhood trauma activates the stress response systems and dysregulates serotonin transmission that can adversely impact brain development. Smaller cerebral, cerebellar, prefrontal cortex, and corpus callosum volumes were reported in maltreated young people as well as reduced hippocampal activity.

Environmental enrichment has a series of beneficial effects associated with neuroplasticity mechanisms, increasing hippocampal volume, and enhancing dorsal dentate gyrus-specific differences in gene expression. Environmental enrichment after prenatal stress decreases depressive-like behaviors and fear, and improves cognitive deficits.”


The reviewers presented strong evidence until the Possible Factors for Reversibility section, which ended with the assertion:

“All these positive environmental experiences mentioned in this section could counterbalance the detrimental effects of early life adversities, making individuals resilient to brain alterations and development of later psychopathology.”

The review’s penultimate sentence recognized that research is seldom done on direct treatments of causes:

“The cross-sectional nature of most epigenetic studies and the tissue specificity of the epigenetic changes are still challenges.”

Cross-sectional studies won’t provide definitive data on cause-and-effect relationships.

The question that remains to be examined is: How can humans best address these early-life causes to ameliorate their lifelong effects?

https://onlinelibrary.wiley.com/doi/full/10.1111/dmcn.14182 “Early environmental influences on the development of children’s brain structure and function” (not freely available)

Epigenetic transgenerational inheritance mechanisms that lead to prostate disease

This 2019 Washington rodent study found:

“Ancestral exposure to the toxicant vinclozolin induces an epigenetic transgenerational increase in susceptibility to prostate pathology in F3 [male great-grandchildren] generation rats. These results are in agreement with previous studies which found a transgenerational increase in rates of prostatic epithelial atrophy, cystic hyperplasia, and prostatitis in the transgenerational F3 and F4 [male great-great-grandchildren] generations after exposure of F0 [great-great-grandmother] generation pregnant rats to vinclozolin. These effects were accompanied by transgenerational changes in mRNA expression in F3 generation ventral prostate epithelial cells.

A number of previous transgenerational studies have shown no ventral prostate histopathology or disease detected. Therefore, observations suggest ancestral exposure specificity in the ability to induce the transgenerational inheritance of prostate disease.

There was also no increase in prostate histopathology in the directly exposed F1 [male children] or F2 [male grandchildren] generation vinclozolin lineage rats compared to controls.

prostate pathology

The mechanism by which epigenetic transgenerational inheritance affects prostate epithelium involves control of gene expression by DNA methylation and lncRNAs. It will be necessary to determine the exact gene targets of these epigenetic modifications to determine further mechanisms.

Future studies need to investigate if similar mechanisms are at work in human males who have adult-onset BPH or prostate cancer. Ancestral exposures to toxicants and epigenetic transgenerational inheritance may contribute to the development of prostate disease in men today.”


The study’s above bolded sentence added to the evidence that epigenetic effects may skip generations. A study by the same group, Epigenetic transgenerational inheritance of ovarian disease, found in females:

There was no increase in ovarian disease in direct fetal exposed F1 or germline exposed F2 generation vinclozolin or DDT lineage rats compared to controls.

A disturbance in the paradigm of child abuse referenced other studies that found generation-skipping effects.

Serious researchers are closer to discovering evidence for precise mechanisms of epigenetic transgenerational inheritance. It’s well past time that other researchers performing studies like Burying human transgenerational epigenetic evidence take their work seriously enough to truly investigate human evidence for epigenetic transgenerational inheritance.

What are more important funding priorities than such human studies?

https://www.nature.com/articles/s41598-019-38741-1 “Environmental Toxicant Induced Epigenetic Transgenerational Inheritance of Prostate Pathology and Stromal-Epithelial Cell Epigenome and Transcriptome Alterations: Ancestral Origins of Prostate Disease”

Disproving the cholesterol paradigm

This 2018 review presented evidence that:

“For half a century, a high level of total cholesterol (TC) or low-density lipoprotein cholesterol (LDL-C) has been considered to be the major cause of atherosclerosis and cardiovascular disease (CVD), and statin treatment has been widely promoted for cardiovascular prevention. However, there is an increasing understanding that the mechanisms are more complicated and that statin treatment, in particular when used as primary prevention, is of doubtful benefit.

The authors of three large reviews recently published by statin advocates have attempted to validate the current dogma. This article delineates the serious errors in these three reviews as well as other obvious falsifications of the cholesterol hypothesis.

Our search for falsifications of the cholesterol hypothesis confirms that it is unable to satisfy any of the Bradford Hill criteria for causality and that the conclusions of the authors of the three reviews are based on:

  • Misleading statistics,
  • Exclusion of unsuccessful trials and by
  • Ignoring numerous contradictory observations.

The association between the absolute risk reduction of total mortality in 26 statin trials [squares] included in the study by Silverman et al. and in 11 ignored trials [triangles] and the year where the trial protocols were published. The vertical line indicates the year where the new trial regulations were introduced.

In 2004–2005, health authorities in Europe and the United States introduced New Clinical Trial Regulations, which specified that all trial data had to be made public. Since 2005, claims of benefit from statin trials have virtually disappeared.


This paradigm was proven wrong eighty years ago! How much longer will its harmful consequences continue?

https://www.tandfonline.com/doi/full/10.1080/17512433.2018.1519391 “LDL-C does not cause cardiovascular disease: a comprehensive review of the current literature”

An hour of the epigenetic clock

This 2018 presentation by the founder of the epigenetic clock method described the state of the art up through July 2018. The webinar was given on the release day of The epigenetic clock now includes skin study.


Segments before the half-hour mark provide an introduction to the method and several details about the concurrently-released study. The Q&A section starts a little before the hour mark.

Stuck in the wrong paradigm

This 2019 article questioned the paradigm of determining substance carcinogenicity:

“In the absence of robust epidemiological data, the final arbiter of whether a chemical is considered to be a carcinogen or not has been based on the outcome of long-term rodent bioassays. This approach is incompatible with the current knowledge of the etiology of cancer. The current view of the etiology of cancer suggests that it is not useful to consider carcinogenicity as a single hazardous property with its own hazard category.

There is no bright line between carcinogens and non-carcinogens but rather there is a continuum with some chemicals having high potential, some having no potential, and others having potential at a point along the continuum. This continuum exists alongside other adverse effects. One problem is being stuck in the old practice of wishing to reproduce the binary “carcinogen/non-carcinogen” results of the long-term bioassay rather than move to a new paradigm in assessing the chemical’s position on the spectrum of carcinogenic potential.

The two-year bioassay has such high variability (because of the variability of the carcinogenic process it is trying to measure and the interplay between dose limiting toxicity and cell proliferation inducing toxicity) that the outcome of the assay for compounds with low to intermediate carcinogenic potential is little more than a lottery. After half a century, it has only been used to evaluate less than 5% of chemicals that are in use. It is not reproducible because of the probabalistic nature of the process it is evaluating combined with dose limiting toxicity, dose selection, and study design.”


Unscientific research paradigms will eventually collapse because they can’t withstand the scrutiny of the scientific method. Too bad the coauthors didn’t kill off this one while they were still in positions at the U.S. Environmental Protection Agency, World Health Organization, etc.

https://www.sciencedirect.com/science/article/pii/S0273230019300248 “Chemical carcinogenicity revisited 2: Current knowledge of carcinogenesis shows that categorization as a carcinogen or non-carcinogen is not scientifically credible” (not freely available)