Your friends and family don’t spend enough time with you – not only is it annoying, but it can also shorten your life expectancy.

A joint research team from Harvard University, Mass General Hospital, and the University of CaliforniaSan Francisco, found eight key factors that can predict how long a person will live.

These loneliness included and not seeing children on the one hand, and living in a dirty neighborhood or feeling treated with less respect by others.

The researchers note that while many consider only medical factors, social health may also play a key role in longevity.

They warned that loneliness shortens life expectancy because it is associated with higher levels of stress, which increases the risk of many chronic diseases. Others were linked to problems with access to good health care and a balanced diet.

Dr. Sachin Shah, a physician scientist and faculty member at Harvard who led the study, said: “We often overemphasize the importance of medical conditions when we think about longevity.

‘[But] this study demonstrates that our social lives are just as important as our medical conditions.”

He added: “From our data, we developed a 10-question survey that uses age, gender and social characteristics to predict longevity. This survey also predicts other outcomes important to older adults, such as independent living.”

Among the eight facts were living in a dirty area, seeing children less than once a year and not participating in the community through activities such as volunteering (listed below).

In a study published this week in the journal PNASResearchers analyzed results from the University of Michigan Health and Retirement Study, which included 20,000 people age 50 and older.

The team used the results to construct a 10-question survey that can predict longevity – called the Social Frailty Index.

Here, people are asked about their age and gender and whether they have children, before being asked whether they feel isolated and how often they interact with others.

Several studies have shown that loneliness poses the same risk as factors such as smoking, obesity and lack of physical exercise to shorten a person’s life.

Researchers say this is because people who live alone have higher levels of stress – or higher levels of the body’s stress hormone cortisol.

Scientists warn that it increases the risk of a host of health problems, including heart disease, Alzheimer’s disease and high blood pressure.

Other studies also show that being out of work increases a person’s risk of shortening their lifespan.

Reasons for this include higher levels of stress, as well as less ability to afford good health care or a balanced diet.

It is not clear why other factors, such as the presence of unclean streets, may lead to earlier death.

But this may be because they are an indicator of socioeconomic status and, as a result, access to health care or a more balanced diet.