Pain, functional limitations, and aging

Abstract

Objectives: To examine the relationship between functional limitations and pain across a spectrum of age, ranging from mid life to advanced old age.

Design: Cross-sectional study.

Setting: The 2004 Health and Retirement Study (HRS), a nationally representative study of community-living persons aged 50 and older.

Participants: Eighteen thousand five hundred thirty-one participants in the 2004 HRS.

Measurements: Participants who reported that they were often troubled by pain that was moderate or severe most of the time were defined as having significant pain. For each of four functional domains, subjects were classified according to their degree of functional limitation: mobility (able to jog 1 mile, able to walk several blocks, able to walk one block, unable to walk one block), stair climbing (able to climb several flights, able to climb one flight, not able to climb a flight), upper extremity tasks (able to do 3, 2, 1, or 0), and activity of daily living (ADL) function (able to do without difficulty, had difficulty but able to do without help, need help).

Results: Twenty-four percent of participants had significant pain. Across all four domains, participants with pain had much higher rates of functional limitations than subjects without pain. Participants with pain were similar in terms of their degree of functional limitation to participants 2 to 3 decades older. For example, for mobility, of subjects aged 50 to 59 without pain, 37% were able to jog 1 mile, 91% were able to walk several blocks, and 96% were able to walk one block without difficulty. In contrast, of subjects aged 50 to 59 with pain, 9% were able to jog 1 mile, 50% were able to walk several blocks, and 69% were able to walk one block without difficulty. Subjects aged 50 to 59 with pain were similar in terms of mobility limitations to subjects aged 80 to 89 without pain, of whom 4% were able to jog 1 mile, 55% were able to walk several blocks, and 72% were able to walk one block without difficulty. After adjustment for demographic characteristics, socioeconomic status, comorbid conditions, depression, obesity, and health habits, across all four measures, participants with significant pain were at much higher risk for having functional limitations (adjusted odds ratio (AOR)=2.85, 95% confidence interval (CI)=2.20-3.69, for mobility; AOR=2.84, 95% CI=2.48-3.26, for stair climbing; AOR=3.96, 95% CI=3.43-4.58, for upper extremity tasks; and AOR=4.33; 95% CI=3.71-5.06, for ADL function).

Conclusion: Subjects with pain develop the functional limitations classically associated with aging at much earlier ages.

Figure 1

Limitations in four domains of functioning across age in subjects with and without pain. (A) Subjects were classified according the highest mobility level they could perform without difficulty: able to jog 1 mile, walk several blocks, walk one block, or unable to walk one block. (B) Subjects were classified according to the highest level of stair climbing ability they could perform without difficulty: able to climb several flights, able to climb one flight, or not able to climb one flight. (C) Subjects were classified according to how many of three upper extremity tasks they could perform without difficulty: extending their arms above their shoulders, pulling or pushing large objects like a living room chair, or lifting or carrying weights over 10 pounds like a heavy bag of groceries. (D) Subjects were classified according to their ability to perform basic activities of daily living (ADLs): able to do all without difficulty, having difficulty with at least one but still able to do without help, or needing help.