People Age at Different Rates

 

Elliott ML, Belsky DW, Knodt AR, Ireland D, Melzer TR, Poulton R, Ramrakha S, Caspi A, Moffitt TE, Hariri AR. Brain-age in midlife is associated with accelerated biological aging and cognitive decline in a longitudinal birth cohort. Mol Psychiatry. 2021 Aug;26(8):3829-3838. doi: 10.1038/s41380-019-0626-7. Epub 2019 Dec 10. PMID: 31822815; PMCID: PMC7282987.

from Elliott et al

This spring and summer my husband and I turn 70. We are old – three score and ten.  According to the Dunedin Study, Chronological age is a poor proxy for biological age, though they have only measured aging up to 45 chronological years so far.

The Dunedin Study covers the aging process in in a group of just over a thousand people born in 1972 or 1973 in Dunedin, New Zealand from age 26 to 45 years old (so far) and reports on the study participants aging process. It is an aging study that has been ongoing for over 20 years.

The researchers tested associations between midlife biological aging and indicators of future frailty risk in the Dunedin cohort of 1,037 infants born the same year and followed (so far) to age 45. Participants’ ‘Pace of Aging’ was quantified by tracking declining function in 19 biomarkers indexing the cardiovascular, metabolic, renal, immune, dental and pulmonary systems across ages 26, 32, 38 and 45 years. At age 45 in 2019, participants with faster Pace of Aging had more cognitive difficulties, signs of advanced brain aging, diminished sensory–motor functions, older appearances and more pessimistic perceptions of aging.

from Elliott et al

Among older adults of the same chronological age, those with accelerated biological aging (as measured by blood and DNA methylation biomarkers) are more likely to develop heart disease, diabetes and cancer and have a higher rate of cognitive decline, disability and mortality. Because all study members were born in 1972–1973, the differences in biological aging can be directly measured. The Dunedin Study has very low attrition rates; the full range of health is represented by the group. The researchers have so far  collected four waves of biological measurements from age 26 to age 45—a unique dataset allowing for more accurate estimates of biological aging. Fourth, although age-related diseases are uncommon in midlife, study members were assessed at age 45 with a battery of established measures that are commonly used in geriatric settings to predict frailty, morbidity and mortality.

In the Dunedin cohort of midlife adults, biomarkers examined by the researchers showed a pattern of age-dependent decline in the functioning of multiple organ systems over the 20-year study period.

However, study members showed wide variation in their Pace of Aging. Over the two decades in which we measured biological aging, the study member with the slowest Pace of Aging aged by just 0.40 biological years per chronological year, while the study member with the fastest Pace of Aging accrued 2.44 biological years per chronological year  

from Elliott et al