HEALTH

Are friends bad for your health?

AT the start of a new year, lots of people will resolve to make a healthy lifestyle change. Many find resolutions like cutting back on unhealthy snacks or taking part in a weekend fitness class easier when friends and family are making the same changes.
However, not all decisions affecting our health are intentional, as we copy the behaviour of friends, colleagues and family who we relate to and admire. Unfortunately, we also imitate habits that are bad for our health, like smoking or eating too much.
This phenomenon means non-contagious conditions like heart disease, strokes and cancer can appear to spread from person to person like an infection.
Can your friends make you obese?

People whom we value and are in regular contact with, form our social network. The Framingham Heart Study has studied the power of social networks since the late 1940s, by tracking three generations of residents in Framingham, a Massachusetts city.
The research indicated a person was far more likely to become obese if someone in their circle had also become obese. It suggested they were 57 per cent more likely if it was a friend, 40 per cent if it was a sibling, and 37 per cent if it was their spouse. The effect was more pronounced if the two people were of the same gender, and was linked to how strongly the individual felt about the other person.
For example, the Framingham study indicated a person’s weight was not affected by that of a neighbour they saw daily if they didn’t have a close relationship. In unbalanced friendships, the person who saw the friendship as important was more likely to put on weight if their “friend” did, but not the other way around.
The level of divorce, smoking and alcohol drinking also appeared to spread via friends and family.
These findings are important. Although we are affected by ageing and can be predisposed to certain conditions, our risk of developing the most common non-infectious diseases is significantly increased by certain behaviours:

• Whether you smoke
• Your diet
• How much physical activity you do
• How much alcohol you drink
• These non-infectious conditions – including heart disease, stroke, cancer, diabetes and lung disease – cause seven out of every 10 deaths globally and nearly 90% of all deaths in the UK.

Social networks may also affect our behaviour and mood.
Perhaps unsurprisingly, smoking in teenagers may be influenced by popularity. When popular adolescents smoke, overall levels of smoking increase and the number of people who quit falls.
Separately, young people whose friends suffered from low mood were found to be more likely to develop low mood themselves and vice versa.
These symptoms didn’t amount to clinical depression, which was not found to spread. But low mood is known to affect teenagers’ quality of life and can sometimes lead to greater risk of clinical depression later on.
The idea that emotions are catching is backed up by a controversial experiment secretly conducted on almost 700,000 Facebook users. The experiment selectively filtered what could be seen on users’ news feeds, which use an algorithm to show relevant posts from their Facebook friends.
Two parallel experiments were conducted; one reduced users’ exposure to posts displaying positive emotion, while the other reduced exposure to posts featuring negative emotion.
Users who encountered positive posts were more likely to post positively themselves, and vice versa. This suggests emotions may spread through online social networks, despite a lack of face-to-face interaction or body language cues.
One criticism levelled at studies of our social networks is that we become friends with people who already have similar traits to us or are in a similar situation. But many studies try to account for this theory, known as social contagion.
If we copy the behaviour of friends and family, how can we harness this trait for good?
Dry January and Veganuary – which encourage people to give up alcohol or go vegan – are high-profile examples of collective attempts to become healthier.
* This analysis piece was commissioned by the BBC from an expert working for an outside organisation.

Exposure to dogs may lessen risks

EVER since humans domesticated the dog, the faithful, obedient and protective animal has provided its owner with companionship and emotional well-being.
Now, a study from Johns Hopkins Medicine suggests that being around “man’s best friend” from an early age may have a health benefit as well — lessening the chance of developing schizophrenia as an adult.
And while Fido may help prevent that condition, the jury is still out on whether or not there’s any link, positive or negative, between being raised with Fluffy the cat and later developing either schizophrenia or bipolar disorder.
“Serious psychiatric disorders have been associated with alterations in the immune system linked to environmental exposures in early life, and since household pets are often among the first things with which children have close contact, it was logical for us to explore the possibilities of a connection between the two,” says Robert Yolken, M.D., chair of the Stanley Division of Pediatric Neurovirology and professor of neurovirology in pediatrics at the Johns Hopkins Children’s Center, and lead author of a research paper recently posted online in the journal PLOS One.
In the study, Yolken and colleagues at Sheppard Pratt Health System in Baltimore investigated the relationship between exposure to a household pet cat or dog during the first 12 years of life and a later diagnosis of schizophrenia or bipolar disorder.

For schizophrenia, the researchers were surprised to see a statistically significant decrease in the risk of a person developing the disorder if exposed to a dog early in life. Across the entire age range studied, there was no significant link between dogs and bipolar disorder, or between cats and either psychiatric disorder.
The researchers caution that more studies are needed to confirm these findings, to search for the factors behind any strongly supported links, and to more precisely define the actual risks of developing psychiatric disorders from exposing infants and children under age 13 to pet cats and dogs.
According to the American Pet Products Association’s most recent National Pet Owners Survey, there are 94 million pet cats and 90 million pet dogs in the United States.
Previous studies have identified early life exposures to pet cats and dogs as environmental factors that may alter the immune system through various means, including allergic responses, contact with zoonotic (animal) bacteria and viruses, changes in a home’s microbiome, and pet-induced stress reduction effects on human brain chemistry. –Science Daily
Some investigators, Yolken notes, suspect that this “immune modulation” may alter the risk of developing psychiatric disorders to which a person is genetically or otherwise predisposed.
In their current study, Yolken and colleagues looked at a population of 1,371 men and women between the ages of 18 and 65 that consisted of 396 people with schizophrenia, 381 with bipolar disorder and 594 controls. Information documented about each person included age, gender, race/ethnicity, place of birth and highest level of parental education (as a measure of socioeconomic status).
Patients with schizophrenia and bipolar disorder were recruited from inpatient, day hospital and rehabilitation programs of Sheppard Pratt Health System. Control group members were recruited from the Baltimore area and were screened to rule out any current or past psychiatric disorders.
– Science Daily