Green’s Dictionary of Slang

old age and its deleterious effects, esp. on physical prowess.

1885		F. Gale Hon. R. Grimston xvi 284: Whenever he felt less able to do things than formerly, he used to say he was afraid ‘Anno Domini’ was the cause [OED].
1892		F. Pollock Leading Cases 93: Yet nothing mortal may deny The march of Anno Domini Not e’en the Senior Fellow [OED].
1906		E.V. Lucas Fireside and Sunshine 186: When the time came for A. to take the bat he was unable to do so. Anno Domini asserted itself.
1917		Kent & Sussex Courier 16 Feb. 4/1: Each writer has passed the mid-period of life [...] One must reckon the symptoms they record as eveideence of a disease a wit has called Anno Domini — just years.
1921		Times 31 Mar. n.p.: My resignation is due to what we call the anno Domini clause, which has come into operation.
1924		Portsmouth Eve. News 29 Oct. 5/2: [headline] Anno Domini. Dairy Show Eggs Disqualified for Old Age.
1925		N. Lucas Autobiog. of a Thief 39: She was verging on early middle age, so far as mere anno Domini went, but she had very young ideas.
1931		Western Dl Press 19 June 5/4: Anno Domini [...] Both the ladies were very old — one of them was 71.
1941		Birmingham Mail 19 Apr. 2/8: Anno Domini. The list of active city justices is likely to be curtailed [...] it is likely that the normal age of retirement for justices will be 75.