Ivan Kelley appeals the District Court’s 2 order affirming the denial of disability insurance benefits. Having carefully reviewed the record, see Roberts v. Apfel, 222 F.3d 466, 468 (8th Cir. 2000) (standard of review), we affirm.

In his July 1988 application, Kelley alleged disability since December 1984 from back problems and a hearing loss. His date last insured was March 1986. After four administrative hearings, three of which occurred after remand by the District Court or the Appeals Council, the Appeals Council assumed jurisdiction and found him not disabled before March 1986.

Kelley argues that the absence of a diagnosis before his date last insured did not preclude a finding of disability. To the extent Kelley offers chiropractor Tom Taylor’s 1993 opinion as to his pre-1986 disability status as a retrospective medical diagnosis, see Grebenick v. Chater, 121 F.3d 1193, 1199 (8th Cir. 1997), and Kelley’s statements to his doctors in 1985 as corroboration, see List v. Apfel, 169 F.3d 1148, 1149 (8th Cir. 1999), Kelley’s approach fails. Chiropractors are not acceptable medical sources, see 20 C.F.R. § 404.1513(a) (2001), and in any event, Dr. Taylor did not begin treating Kelley until October 1988 and offered no basis for his opinion about Kelley’s pre-1986 condition. While Kelley’s borderline intellectual functioning, first diagnosed in May 1991, is a severe impairment, see Hunt v. Massa-nari, 250 F.3d 622, 625 (8th Cir. 2001), Kelley worked with it for a number of years and there is no concrete evidence that it worsened before his date last insured, see Roberts, 222 F.3d at 469.

We have considered the other points Kelley raises, and conclude they provide no basis for remand. Accordingly, we affirm. See 8th Cir. R. 47B.