(RxWiki News) Unhealthy habits may seem unimportant when you're young. However, some habits may be shaving off a significant amount of years from your life.
A recent study added more evidence that lifestyle risk factors such as cigarette smoking and an unhealthy body weight were associated with a shorter life expectancy in middle-aged adults.
The researchers concluded that the promotion of healthy lifestyle should be a main component of public health approaches to reducing premature death.
"Adopt healthy habits today."
The lead author of this study was Kuanrong Li, PhD, from the Division of Cancer Epidemiology at the German Cancer Research Centre in Heidelberg, Germany.
The study included 22,469 German adults who were recruited between 1994 and 1998 for an ongoing study called the European Prospective Investigation Into Cancer and Nutrition (EPIC).
The current study by Dr. Li and team included 10,235 men and 12,234 women, all of whom were 40 years old and older. The average age of the women was 49 years old and the average age of the men was 52 years old.
None of the participants had pre-existing diabetes, heart disease or cancer when recruited.
The participants were interviewed on their current and lifetime smoking status, alcohol consumption, average time spent doing physical activity during their leisure time and their food consumption over the previous 12 months. Height and weight were also measured to determine the participants' body mass index (height to weight ratio).
A very low body mass index (BMI) was defined as lower than 22.5 kg/m2; a healthy BMI was between 22.5 and 24.9 kg/m2; a BMI between 25 and 29.9 kg/m2 was considered overweight; and obesity was defined as a BMI over 30 kg/m2.
The researchers conducted follow-up for an average of 11 years. Instances of death were identified through the official German death registry system or the participant's family. The researchers verified each case by obtaining a death certificate.
The findings showed that 1,599 participants died during follow-up. Of these people who died, 1,040 were men and 559 were women.
Overall, smoking cigarettes was most associated with decreased life expectancy.
The life expectancy of the men and women who smoked more than 10 cigarettes per day was reduced by nine and seven years, respectively. The men and women who smoked 10 or fewer cigarettes per day had a life expectancy reduction of five years.
The researchers found that very low BMI and obesity were associated with a lower life expectancy for both the men and women.
The men's life expectancy was reduced due to heavy drinking, and the women's life expectancy was reduced due to eating over 120 grams of processed or red meat per day.
The findings also revealed that the obesity-related decrease in life expectancy was more significant among the men who never smoked compared to the men who ever smoked.
However, the decrease in life expectancy related to having an abnormally low BMI was more significant among the men who were current smokers.
Low physical activity during leisure time was moderately associated with a reduction of life expectancy in the women; the association was insignificant among the men.
Dr. Li and team estimated that the combined behaviors of heavy smoking, obesity, heavy drinking and eating more than 120 grams of processed or red meat reduced the men's life expectancy by 17 years and the women's lives by 14 years compared to the men and women who never smoked, had a healthy BMI, were not heavy drinkers and ate less meat.
Previous studies have estimated that the average life expectancy of German men is 78 years and 82 years for women. The researchers believe that maintaining a healthy lifestyle could increase the life expectancy of German men and women to 88 years and 89 years.
The researchers suggested that the current gender gap in the life expectancy of middle-aged German adults is due to a higher amount of men engaging in harmful lifestyle behaviors compared to women.
The study had some limitations. First, the effects of each lifestyle risk factor were determined as if each behavior was constant over time. Second, the study participants were aged 40 to 82 years old, so these findings may not apply to adults of other ages.
Third, it is hard to accurately measure diet and physical activity. Fourth, these findings may not be generalizable outside of the German population.
This study was published on April 7 in BMC Medicine.