Fitness And Dementia; Smarter PSA Testing For Prostate Cancer: Annals Of Internal Medicine Feb. 5, 2013
1. Being Physically Fit Earlier in Life May Lower Risk for Dementia Later in Life
Having a higher fitness level at midlife seems to be associated with lower hazards of developing Alzheimer disease and other types of dementia later in life. Between 1970 and 2009, researchers at a community health clinic utilized an exercise treadmill test to assess the baseline fitness levels of 19,458 non-elderly, community-dwelling adults who were in generally good health. The researchers reviewed Medicare data for the patients who became eligible to receive benefits between January 1, 1999 and December 31, 2009 to assess the association between objectively measured midlife fitness levels and development of all-cause dementia in advanced age. A diagnosis of all-cause dementia was defined as at least one inpatient, skilled-nursing facility, home health agency, hospital outpatient, or physician or supplier claim with any diagnosis code corresponding with Alzheimer disease, senile dementia, and presenile dementia among persons having at least three years of Medicare coverage. Four codes corresponding with vascular dementia were also included. The researchers documented the presence or absence of dementia in all living patients at ages 70, 75, 80, and 85. They found that patients who were physically fit earlier in life were much less likely to develop dementia than those who were less fit. The author of an accompanying editorial notes that despite ample evidence that physical activity is associated with many health benefits, it can be difficult to get patients to adhere to an exercise program. The author writes that the association with reduced risk for Alzheimer’s – one of the most feared diseases among U.S. adults – may entice patients to increase physical activity.
2. ‘Smarter’ PSA Testing May Reduce Harms of Testing While Preserving Life-saving Benefits
Using a selective screening strategy for prostate cancer may reduce the harms associated with testing while preserving the number of lives saved. Measuring blood levels of prostate-specific antigen (PSA) can help doctors determine which patients may be at risk for prostate cancer. Patients with an elevated PSA level may require a biopsy to determine if cancer is present. However, biopsies are associated with many troublesome side effects and still cannot tell a doctor with certainty which cases of prostate cancer are life-threatening and require treatment. Current prostate cancer screening guidelines have been the source of controversy. While only one guideline recommends against screening altogether, others are less clear, recommending informed decision-making on an individual level. This can be difficult because there is sparse data available to help doctors have nuanced conversations with their patients about whether and how often to have prostate cancer screening. Researchers used a computer model to compare 35 screening strategies that varied in terms of age of first and last screening, screening intervals, and PSA thresholds for biopsy referral. The researchers looked at false-positive results, cancer detected, overdiagnoses (cancers detected that would otherwise never become clinically significant), deaths from prostate cancer, lives saved, and months of life saved. They found that compared with a standard screening strategy, using higher thresholds for biopsy referral for older men and screening men with initially low PSA levels less frequently may be a way to improve the tradeoff between screening and overdiagnosis. The author of an accompanying editorial does not believe this study will do much to quiet the debate on whether to screen for prostate cancer. The author notes the many limitations of the model which does not consider important factors such as race and family history, patient preferences, or potential complication of incontinence or impotence. As the debate rages on, the author suggests that physicians engage in shared decision-making with patients with regard to prostate cancer screening.
American College of Physicians