I am halfway through my 69th year on the planet. I grew up in an age devoid of any electronic devices that would keep me indoors, so outdoor activities typical of the day were the norm, and it was not sedentary. I played sports as I got older, as well as water polo and club rugby while in college, and triathlons after college until my wife and I began having children.
At this point, I maintained a lunchtime routine during the work week, swimming 3000 yards during my lunch break at the YMCA and training on various pieces of equipment at the rehabilitation facility where I worked. My blood pressure, lab work, and weight have always been normal or somewhere close by, except for the occasional bump in cholesterol levels to 220 or so.
I have never refrained from the typical minor number of sweets in my diet, and living in a region where summertime temperatures are routinely 100+ for 3-4 months of the year, sometimes daily for 30 days or more, ice cream tends to take the edge off the debilitating effects of chronic heat.
Aging is not for the Weak
I recently retired but remain very active, but the physician I used for decades if I needed it, retired, so I needed to choose a new one young enough who I hoped would remain in practice far beyond whatever years I have left. My initial visit required the typical lab work as a baseline, which I had not done since 2015.
The labs and blood pressure were normal except for cholesterol, 220, which is typical, and blood sugar of 107 vs 88 in 2015. He requested an HgA1c test due to my glucose levels, which returned as 6.3, typically defined as “pre-diabetic,” which, of course, totally surprised me. As a heavy plant-based omnivore, very physically active, and with no diabetes in any member of a large family, his comment was surprising.
So, for the next three months, the time frame required to impact the HbA1c, I followed the diet from hell. I refrained from all ice cream, cookies, etc., and shed 10 pounds to see its effect on my A1c and blood sugar levels. After three months, my HA1c dropped to a “whopping” 6.2 from its peak of 6.3, my blood sugar from 107 mg/dl to 106 mg/dl – hardly impressive with all the dietary restrictions and weight loss.
Obviously, there was more to this number than just my dietary habits. On a follow-up visit, I shared with my physician this research, which had appeared in BMC Endocrine Disorders back in 2019.
Reference values for HbA1c were established in 1986 based on a small population of 124 non-diabetic individuals with a limited age range of 13–39 years, and these reference values have not been subject to change since then. [1] Glycemia and metabolic control change with age, and several studies reported increased HbA1c in elderly non-diabetic individuals. Clinical guidelines currently in use still rely on those initial reference values without accounting for the influence of age.
The researchers examined two population-based cohorts containing roughly 8600 healthy individuals without diabetes between 20 and 79 for age-specific changes in HbA1c.
- The positive association of HbA1c with age previously shown in several populations of different ethnicities, the Framingham Offspring study, and the National Health and Nutrition Examination Survey 2001–2004 (NHANES) was confirmed.
- The positive association of the HbA1c concentration with age was observed equally in lean, overweight, and obese individuals.
- There was an increase of HbA1c of 0.153% per decade in men and a comparable increase of 0.191% per decade in women
The authors concluded,
“The present study confirmed the previously observed increase of HbA1c with increasing age in non-diabetic individuals. This association between HbA1c and age was found to be independent of BMI. The underlying reasons remain to be elucidated. However, with reference values that disregard the age-related increase of HbA1c, potential overtreatment and the risk of misdiagnosis of diabetes in the elderly may be the consequence. Therefore, our study for the first time provides age-dependent reference values for HbA1c. Awareness of clinicians of the age-related increase of HbA1c independent of diabetes and the transition of this fact into age-dependent reference intervals may improve patient care and diagnosis of diabetes.”
Diagnostic Clarity
The ADA has now established criteria for an intermediate group whose fasting glucose levels, HbA1c, or fasting glucose tolerance test are neither normal nor clearly diabetic. These individuals, commonly referred to as having pre-diabetes, have a higher risk of developing diabetes and its complications. These criteria include:
- Fasting blood sugar of 100 mg/dl to 125 mg/dl,
- HbA1c of 5.7 - 6.4 %
- 2-hour impaired glucose tolerance test of 140 mg/dl to 199 mg/dl.
For reasons of cost and convenience, most screening for pre-diabetes is done simply with the HbA1c, and few patients are asked to undergo a glucose tolerance test. In most instances, when the HbA1c is elevated into the 5.7 to 6.4% range, your physician recommends lifestyle interventions to increase physical activity and lose body fat.
After discussing this with my physician, reiterating the dietary effort, weight loss, as well as continuing 5-day per week training regimens, he remained firm, holding to the standard values most do, portraying me as pre-diabetic. So, to settle the debate, I followed through with a more diagnostically accurate 2-hour glucose tolerance test. [2}
My response at two hours was a blood sugar of 73mg/dL, well within the ADA’s normal range. While this is only one case, an N of 1, the findings certainly support the need to adjust the HbA1c standards per decade of life and not the one standard fit all, which is so prevalent.
I chucked the diet from hell.
[1] I contacted the American Diabetic Association by email on September 9 to clarify this. Still, my only response as of September 23 is, “Your email has been forwarded to the proper department.”
[2] ] The test involves choking down 75 mg of a glucose solution after an overnight fast and measuring the blood sugar response at 30 minutes, 1 hour, and 2 hours post imbibing.
