Two new studies that reinforce old points. The first is from the JAMA (Effect of a Low-Intensity PSA-Based Screening Intervention on Prostate Cancer Mortality ):

Question  What is the effect of an invitation to a single prostate-specific antigen (PSA) screening on prostate cancer detection and median 10-year prostate cancer mortality?

Findings  In this randomized clinical trial comparing men aged 50 to 69 years undergoing a single PSA screening (n = 189, 386) vs controls not undergoing a PSA screening (n = 219 ,439), the proportion of men diagnosed with prostate cancer was higher in the intervention group (4.3%) than in the control group (3.6%); however, there was no significant difference in prostate cancer mortality (0.30 per 1000 person-years for the intervention group vs 0.31 for the control group) after a median follow-up of 10 years.

Meaning  The single PSA screening intervention detected more prostate cancer cases but had no significant effect on prostate cancer mortality after a median follow-up of 10 years.

Yet another study showing that PSA screening does not reduce prostate cancer death. The US Preventive Services Task Force Recommendation Statement regarding prostate cancer screening is below:

For men aged 55 to 69 years, the decision to undergo periodic PSA-based screening for prostate cancer should be an individual one and should include discussion of the potential benefits and harms of screening with their clinician. Screening offers a small potential benefit of reducing the chance of death from prostate cancer in some men. However, many men will experience potential harms of screening, including false-positive results that require additional testing and possible prostate biopsy; overdiagnosis and overtreatment; and treatment complications, such as incontinence and erectile dysfunction. In determining whether this service is appropriate in individual cases, patients and clinicians should consider the balance of benefits and harms on the basis of family history, race/ethnicity, comorbid medical conditions, patient values about the benefits and harms of screening and treatment-specific outcomes, and other health needs. Clinicians should not screen men who do not express a preference for screening. (C recommendation) The USPSTF recommends against PSA-based screening for prostate cancer in men 70 years and older. (D recommendation)

You’ve likely seen recommendations to drink extra water, ie more than thirst requires. If you’re sedentary, in an air conditioned environment, and don’t have kidney stones there’s no evidence that extra water conveys any health benefit. There are a few serious diseases in which excess water intake may be harmful. A study also in the JAMA (Effect of Coaching to Increase Water Intake on Kidney Function Decline in Adults With Chronic Kidney Disease) looked at the course of kidney disease in patients coached to ingest more water than they ordinarily would. As you might expect more water has no effect of the course of chronic renal disease:

Question  Does drinking more water protect against declining kidney function in patients with chronic kidney disease?

Findings  In this randomized clinical trial that included 631 adult patients with chronic kidney disease, the 1-year decline in estimated glomerular filtration rate did not significantly differ between patients who were coached to drink more water compared with patients who were coached to maintain their usual intake (−2.2 vs −1.9 mL/min per 1.73 m2).

Meaning  Coaching to increase water intake did not significantly slow the decline in kidney function in patients with chronic kidney disease at 1-year follow-up.

An interesting question. Is medical science coming up with more reasons to stay away from the doctor? If so, nobody is paying attention.