Men suffering from erectile dysfunction (ED) are more likely to be less productive at work and maintain a lower health-related quality of life, says a study.

The study, published in the International Journal of Clinical Practice, showed that erectile dysfunction in men significantly impacts work productivity and adversely affects the quality of life.

Erectile dysfunction (ED) is defined as the persistent inability to achieve and/or maintain penile erection sufficient for performing sexual intercourse.

For the study, the researchers analysed data of more than 52,000 men aged between 40 to 70 years from eight countries -- Brazil, China, France, Germany, Italy, Spain, the UK and the US.

The study showed that the overall ED prevalence was 49.7 per cent, with Italy reporting the highest rate (54.7 per cent).

Men with ED reported significantly higher rates of staying home from work (7.1 per cent versus 3.2 per cent), working while sick (22.5 per cent versus 10.1 per cent), work productivity impairment (24.8 per cent versus 11.2 per cent), and activity impairment (28.6 per cent versus 14.5 per cent) than men without ED.

They also had lower measures of health-related quality of life.

"This study shows that ED remains a prevalent concern, one that impacts work productivity and absenteeism," said co-author Wing Yu Tang, a researcher from Pfizer Inc, New York.

The researchers suggested that better management and earlier detection may help reduce this burden, especially in comparative countries where there is a strong association between erectile dysfunction and these implications for the workplace and overall quality of life.

Coffee lovers, please take note. Drinking three or more servings of caffeinated beverages a day increases the risk of migraine.

In a study published in the American Journal of Medicine, researchers evaluated the role of caffeinated beverages as a potential trigger of migraine.

They found that, among patients who experience episodic migraine, one to two servings of caffeinated beverages were not associated with headaches on that day, but three or more servings of caffeinated beverages may be associated with higher odds of migraine headache occurrence on that day or the following day.

"While some potential triggers - such as lack of sleep - may only increase migraine risk, the role of caffeine is particularly complex, because it may trigger an attack but may also help control symptoms, caffeine's impact depends both on dose and on frequency," said Elizabeth Mostofsky from Harvard University.

During the study, 98 adults with frequent episodic migraine completed electronic diaries every morning and every evening for at least six weeks.

Every day, participants reported the total servings of caffeinated coffee, tea, soda and energy drinks they consumed, as well as filled out twice daily headache reports detailing the onset, duration, intensity, and medications used for migraines since the previous diary entry.

Participants also provided detailed information about other common migraine triggers, including medication use, alcoholic beverage intake, activity levels, depressive symptoms, psychological stress, sleep patterns and menstrual cycles.

To evaluate the link between caffeinated beverage intake and migraine headache on the same day or on the following day, researchers used a self-matched analysis, comparing an individual participant's incidence of migraines on days with caffeinated beverage intake to that same participant's incidence of migraines on days with no caffeinated beverage intake.

The researchers further matched headache incidence by days of the week, eliminating weekend versus week day habits that may also impact migraine occurrence.

Self-matching also allowed for the variations in caffeine dose across different types of beverages and preparations.

"One serving of caffeine is typically defined as eight ounces or one cup of caffeinated coffee, six ounces of tea, a 12-ounce can of soda and a 2-ounce can of an energy drink," Mostofsky said.

"Those servings contain anywhere from 25 to 150 milligrams of caffeine, so we cannot quantify the amount of caffeine that is associated with heightened risk of migraine. However, in this self-matched analysis over only six weeks, each participant's choice and preparation of caffeinated beverages should be fairly consistent," Mostofsky added.

Stressful life experiences such as divorce, death of a loved one or job loss may lead to a greater memory decline and raise the risk of Alzheimer's disease among the middle-aged women, says a new study.

The study's findings, published in the International Journal of Geriatric Psychiatry journal, showed that stress hormones play an uneven gender role in brain health and align with well-documented higher rates of Alzheimer's disease in women than men.

According to the Alzheimer's Association, one in 6 women over age 60 will get Alzheimer's disease, compared with 1 in 11 men. At present, there are no proven treatments that prevent or halt progression of the disease.

"We can't get rid of stressors, but we might adjust the way we respond to the stress, and have a real effect on brain function as we age," said Cynthia Munro, Professor at Johns Hopkins University, US.

"Although our study did not show the same for men, it sheds further light on the effects of the stress response on the brain with potential application to both men and women," she added.

For the study, Munro and her team used data collected on over 900 participants, 63 per cent of the participants were women. Participants were of an average age of 47.

The researchers suggested that the ongoing stress may have more of a negative impact on brain functioning than distinct traumatic events.

"A normal stress response causes a temporary increase in stress hormones like cortisol, and when it's over, levels return to baseline and you recover. But with repeated stress, or with enhanced sensitivity to stress, your body mounts an increased and sustained hormone response that takes longer to recover," said Munro.

"We know if stress hormone levels increase and remain high, this isn't good for the brain's hippocampus -- the seat of memory," Munro added.

The researchers say that stress reduction has not received a whole lot of attention compared with other factors that may contribute to dementia or Alzheimer's, and that it might be worth exploring the stress management techniques as a way to delay or prevent disease.