No single unhealthy age

There is no single age at which all the health signals are worst. Raised blood sugar becomes more common in each older adult band, but the largest low-vitamin shares sit in the twenties, and low HDL and raised liver enzymes peak in the thirties. Even the two survey measures point in different directions: high stress is lower in older bands, while short sleep is highest in the fifties.

That makes age useful for asking which health needs to assess, rather than deciding that one older group carries all of them. The comparison below brings together eight laboratory measures from 11,427 reports and two self-reported measures from 9,097 survey responses.

Ten signals, four peak bands — and none of them is the 40s#

Put every signal on one age axis and sort the rows by the band where the share meeting each definition is highest.

Four bands hold a peak and the 40–49 column holds none, which is not the same as holding no risk: the 40s sit second or third highest on nine of these ten rows. The rows also differ in shape. HbA1c and creatinine are higher in every older band. Vitamin D and B12 are lower in every older band. Uric acid does neither — higher in the 30s than in the 20s, lowest in the 50s, highest at 60 and above.

Laboratory figures count reports from insured employees and covered family; survey figures count responses. The samples are not linked person by person. Laboratory tables cover adults; survey tables cover ages 20–59. The transaminase row uses SGPT or SGOT ≥40 U/L, unlike the Liver page, which uses >40 or GGT >60. HDL here uses <40 for both sexes, not sex-specific criteria.

Raised HbA1c is nearly twice as common in reports from the 30s as the 20s#

HbA1c is the share of haemoglobin carrying bound sugar, and it reflects average blood glucose over about the past three months (NIDDK). This row counts reports at or above 5.7%, where NIDDK places the lower boundary of the prediabetic range; the split between the pre-diabetic and diabetic bands, and the city and sex cuts, are on the Blood Sugar page.

One in six reports in the 20s sits at or above the cut. One in three in the 30s: 33.0% against 16.7%, just short of twice the share. More than half in the 40s, and close to four in five at 60 and above. Only one other row on this page is higher in every older band, and that is creatinine, which runs from 0.3% to 4.1%.

WHI 2025 cut the same 5.7% threshold by named generation rather than by decade, and its two youngest bands are the only ones that come close to these: 15.7% for 22–30 against 16.7% here, and 34.3% for 31–40 against 33.0% here. The band edges differ by a year or two, and the 2026 sample is about four times the size across the marker as a whole, 7,088 tested reports against the 1,649 WHI 2025 analysed. What the pairing supports is that both editions find about one in six and about one in three in their two youngest bands. It is not a movement in anyone's health.

The low-HDL and raised-transaminase shares are highest in the 30s#

HDL is the lipid fraction that carries cholesterol away from artery walls, so a low value is the unfavourable one. SGPT and SGOT, also written ALT and AST, are enzymes that cells release into the blood when they are damaged. ALT sits mainly in the liver and is the more liver-specific of the two; AST is found in the liver but also in the heart, muscle and other tissues (MedlinePlus), so a raised result on this row does not establish which tissue it came from, let alone why.

Both are highest in the 30–39 band, at 49.5% for HDL and 23.1% for the transaminases. The transaminase share at 60 and above is 9.5%, more than half below its 30s peak.

The HDL row applies one cut, below 40 mg/dL, to the reports of both sexes, which is the cut the Lipids page uses for its own distribution. The clinical criterion is sex-specific, below 50 mg/dL for women and below 40 for men (NHLBI), so a single below-40 line classifies fewer women's reports as low than the clinical criterion would, and this row makes no comparison between women and men. The transaminase row counts a report when SGPT or SGOT is at or above 40 U/L, on the reports carrying at least one of the three liver enzymes; no report in that base carries GGT alone. The Liver page uses SGPT or SGOT strictly above 40 U/L, or GGT above 60 U/L. Its share and this one therefore describe different measures.

WHI 2025 also placed its low-HDL peak in its 31–40 band, at 51.7% on 661 results against 49.5% here, with 47.4% on 852 in its 22–30 band against 41.8% here. Those bands cover similar age ranges rather than identical ones, so the pairing supports the peak sitting in a similar range in both editions rather than a measured fall between them.

86.7% of vitamin D results in the 20s are below 30 ng/mL#

Vitamin D is made in skin struck by ultraviolet light and is also taken in from food, from fortified food and from supplements (NIH Office of Dietary Supplements). This row counts reports below 30 ng/mL, which this report's own threshold list calls insufficient, reserving deficient for below 20 and severe for below 10. Those are this report's cutoffs rather than a settled clinical boundary: the same fact sheet states that the serum concentrations associated with vitamin D deficiency have not been definitively identified, and the Endocrine Society's 2024 guideline advises against routine vitamin D testing in generally healthy adults with no established indication. Vitamin B12 comes from foods of animal origin, from fortified foods such as breakfast cereals and nutritional yeasts, and from supplements (ODS), and where the boundary between normal and deficient falls varies by laboratory. This row counts reports below 300 pg/mL, this report's low band, with deficient reserved for below 200. The lower cutoffs, and the city and sex cuts, are on the Vitamin D and Vitamin B12 pages.

Both rows are lower in every older band: B12 runs 76.4% in the 20s against 51.7% at 60 and above, and vitamin D below 30 ng/mL runs 86.7% against 69.4%. The 86.7% share is the highest for any of the ten measures in the adult bands shown.

WHI 2025 cut the same below-300 B12 band by generation rather than by decade, on five bands of its own between 22 and 58, and found the same shape: its share runs from 77.5% in its youngest band down to 56.0% in its oldest. The bands are drawn too differently to subtract one edition from the other, so what the pairing supports is the direction and not a movement. Its vitamin D age list will not pair at all, because it counts results below 20 ng/mL where this row counts below 30.

The creatinine and uric-acid shares are highest at 60 and above#

Creatinine is a waste product made as muscle tissue breaks down, and the kidneys normally clear it from the blood, so a raised level is a signal that filtration may be reduced (MedlinePlus). The same source is explicit that creatinine on its own is not the best way to check how well the kidneys are working, and that a single high result cannot diagnose a specific condition. Uric acid is made when the body breaks down purines and is also cleared by the kidneys (MedlinePlus). The two cutoffs this row applies, above 7 mg/dL for men and above 6 for women, are this report's analysis definitions. Clinical reference ranges can differ by laboratory.

Creatinine above 1.3 mg/dL is higher in each band than in the one before it, from 0.3% in the 20s to 4.1% at 60 and above. It is one of only two rows on this page that do that, and it does it on the smallest shares anywhere in these tables: the whole row rests on 80 raised results among 7,987 reports. Uric acid does not run in one direction: 16.1%, then 18.3%, then 15.3% and 13.0%, then 21.7%, so its lowest band and its highest band sit next to each other.

This row counts a creatinine result strictly above 1.3 mg/dL, matching the definition on the Kidney page. The sex split for both markers is on the Kidney page.

Stress is lower in each older band; short sleep is highest in the 50s#

These two rows come from the survey rather than from a laboratory. Respondents rated their stress over the previous week from 1 to 10, and this row counts the answers from 7 to 10. They also picked a sleep duration from a list of bands, and this row counts the two shortest options, under 5 hours and 5 to 6 hours; it counts the options people chose, not measured hours. The full distributions are on the Sleep and Stress pages.

High stress is lower in each older band, from 42.8% down to 30.5%. Short sleep is not the mirror image of that: 30.1% in the 20s, at its lowest in the 30s at 29.4%, then 34.4%, then 41.0% in the 50s, which is the oldest band here because the 60-and-above cells hold 19 answers each.

WHI 2025 also identified its youngest generation as the group with the highest share reporting high stress. Its age bands were not consistently specified, so the comparison supports that ordering, not a measured change from one edition to the next.

The 50–59 band has only 226 stress and 229 sleep answers, against thousands in younger bands. Small differences are less certain in this older group.

Review screening age rules for each measure#

Four of the eight laboratory measures here reach their highest share below 40 and four at 50 and above. This gives employers a reason to review age-based screening eligibility for each measure, rather than assume that one age rule suits the whole panel. What follows from that for a particular employer depends on its own age distribution and on what its panel actually contains below the gate, and both of those are things a benefits team can ask its provider for.