People with irregular heartbeats are often advised to give up caffeine, but a new study suggests they may not have to forgo coffee.

Researchers had 1,388 people record their intake of coffee, tea and chocolate for a year, and used Holter monitors to get 24-hour electrocardiograms. More than 60 percent of the participants reported consuming one or more caffeine-containing foods daily. But the electrocardiograms revealed no differences in premature beats or episodes of accelerated heart rate between caffeine users and abstainers. The study is in the Journal of the American Heart Association.

"There's no clear evidence that drinking more caffeine increases the risk for early beats," said the senior author, Dr. Gregory M. Marcus, an associate professor of medicine at the University of California, San Francisco. Other studies suggest caffeine may even be linked to decreased rates of cardiovascular problems.

Yes, a lot of pot can harm memory

Research published in the journal JAMA Internal Medicine confirms what many of us have suspected for some time: If you smoke a lot of weed — a lot of it — it can potentially do permanent damage to your short-term memory.

Professor Reto Auer of the University of Lausanne led a team of researchers who examined data on the marijuana habits of nearly 3,400 Americans over a 25-year period. At the end of the study period, the subjects took a battery of tests designed to assess cognitive abilities — memory, focus, ability to make quick decisions, etc. The study found that people who smoked marijuana on daily basis for a long period of time — five years or more — had poorer verbal memory in middle age than people who didn't smoke, or who smoked less.

Mental health and preterm birth

Having a mother or father who is depressed increases the risk of preterm birth, a study has found.

Among mothers, a new diagnosis of depression — getting a depression diagnosis after a year without one — was associated with a 34 percent increased risk of moderately preterm birth (32 to 36 weeks' gestation). Recurrent maternal depression was associated with a 42 percent increased risk.

Recurrent paternal depression was not associated with preterm birth. But new paternal depression increased the risk for moderately preterm birth slightly and the risk for very preterm birth (22 to 31 weeks' gestation) by 38 percent. The Swedish study, in BJOG, used data on 366,499 births.

"The message … is that fathers are also important," said the senior author, Dr. Anders Hjern, an epidemiologist at the Karolinska Institute. "Having a mentally healthy and supportive father who can provide a favorable environment for his partner is also good for the baby. And maternity care interventions should also include the father. Sometimes the father is forgotten."

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