“Alcohol appears to disrupt the healthy balance in the lungs,” says lead author Dr Majid Afshar. In an asthma patient, the amount of exhaled nitric oxide in a breath test provides a good indication of how well the patient’s medication is working. Excessive alcohol consumption might complicate the results of such tests. “Lung doctors may need to take this into consideration,” says Afshar.

Adolescent depression in girls offset by presence of ‘boomerang father’

A new study of the impact of “boomerang fathers” – those who cycle in and out of their children’s lives – has produced surprising results. “Previous research has suggested that stressful experiences, like family instability, father absence or stepfather presence, contribute to an adolescent experiencing depression,” says principal investigator Daphne Hernandez, a University of Houston assistant professor. “This is not what happened in the cases of these youths. Boomerang fathering served as a protective factor for female adolescent depression compared to female adolescents who experienced instability, but not boomerang fathers.”

The study used data from nearly 4,000 young people who were 18 years old by the year 2010, and more than 3,300 mothers, in the US. A third of the daughters sampled had unstable father residential patterns – they never lived with their biological father or they experienced boomerang fathering.

Most households with boomerang fathers did not experience the presence of a step-parent or nonbiological father. “Familiarity of a biological father who enters and exits the house may deter nonbiological partners from entering their children’s lives, lowering the activation of the hormone that causes stress and depression,” Hernandez says. “Although the relationship between the biological father and mother may be complex, there is a commitment to the child by the boomerang father that creates a bond between father and child.”

The researchers say the study’s findings suggest family instability is more fluid and complex than previously thought, indicating greater family support during times of instability may assist in creating positive mental health.

Eating more plant protein associated with lower risk of death

Getting your protein from plant sources such as lentils and tofu instead of animal sources like beef and pork is associated with a lower risk of death. At the same time, eating more protein from animals is associated with a higher risk of death, especially among adults with at least one unhealthy behaviour such as smoking, drinking or being overweight or sedentary. These are the conclusions of a new article published online in JAMAInternal Medicine.

Dr Mingyang Song of Harvard Medical School, Boston and co-authors used data from two large US studies involving a total of 131,342 participants that had repeated measures of diet through food questionnaires and up to 32 years of follow-up. The average age of participants was 49 and about two-thirds were women. Average protein intake, measured as a percentage of calories, was 14 per cent for animal protein and four per cent for plant protein.

After adjusting for major lifestyle and dietary risk factors, every 10 per cent increment of animal protein from total calories was associated with a two per cent higher risk of death from all causes and an eight per cent increased risk of death from cardiovascular disease death. In contrast, eating more plant protein was associated with a 10 per cent lower risk of death from all causes for every three per cent increment of total calories and a 12 per cent lower risk of cardiovascular death.

“Substitution of plant protein for animal protein, especially from processed red meat, may confer substantial health benefits. Therefore, public health recommendations should focus on improvement of protein sources,” the study concludes.