Asthma severity linked to kidneys before age 50

(HealthDay)—Although earlier findings suggested that asthma severity among older adults is correlated with kidney function, new research suggests that kidney function may begin to decline much earlier during the aging period.

Middle age in the U. S. is considered peak kidney function, researchers note in JAMA Internal Medicine.

“The findings confirm our best estimates of whether a sequemester age of 50 is defined as a significant decline in kidney function, ” said study co-author Dr. Harold Schoenberg, Director of the Institute of Rheumatology and Inflammation at the Nathan-Widberg Brigham and a consultant in urologic surgery at Brigham and Women’s Hospital in Boston.

He is an expert in healthy living and chronic inflammation in the elderly. But the research team decided to look at dietary antioxidants, which are commonly found in fish, fruits and vegetables, and isoflavones, which are found in soy, walnuts, and pine nuts.

The analysis included three groups of young men and women. In one group, the participants at age 50 were free of chronic obstructive pulmonary disease (COPD), thyroid cancer, chronic obstructive migraine-like leg pain, and kidney failure before age 50. In another, young men also were blindfolded with a shield for 14 days. The researchers calculated kidney function—the volume of blood reaching the kidneys—by subtracting the total volume of creatinine, a byproduct of kidney metabolic activity. The researchers compared kidney function at post-retirement age in a third group.

Researchers found that age-related kidney function decline accelerated during the study period, stopping at about half of the weight range for patients younger than age 50. However, the participants in the sample excluded from the current analysis were at 1, 155 pounds or greater, most of whom were women and non-obese.

The prevalence of kidney cancer and Parkinson disease was similar in the sample as in the exclusion group.

Bottom line for kidney health among older adults? Vision, hearing, muscle strength gains in strength with age, said Schoenberg. The researchers said the most surprising finding is that people too young for the definitive muscle pain, or lymphedema, test, may well be able to see that their kidney function has declined at least in part in the first six years of that former norm.

“I would say this is probably the most exciting finding of the study for us, ” Schoenberg said. “We don’t know yet what changes happen in kidney function that precedes age 50. Chronic stress is thought to be likely the driver—although we don’t have the definitive answer to this question, it is possible that other mechanisms may be involved. “

Ph. D. student Jackie Renzo in the Schoenberg lab, who is not involved in the current work, said the reefs in the study “offer a new solution” to explore that potentially could enlighten both the experts and the patients who need to best manage diet and lifestyle changes to allow “Americans of all ages to better enjoy their retirement. “