Monday April 7 2014
Sunbeds can cause premature skin ageing
“Teenage men who regularly use sunbeds are more prone to eating disorders,” the Metro reports. A study has found that teen tanners are more likely to engage in unhealthy behaviour, such as using laxatives and vomiting after meals, in order to lose weight or prevent weight gain.
However, it shouldn't it be inferred from these findings that using sunbeds gives you an eating disorder. What it does suggest is that a pattern of unhealthy behaviours may cluster together, with body conscious teens potentially feeling pressurised to be both tanned and thin.
The study involved young people (both males and females) from America, who were given a questionnaire that asked about their use of tanning beds and any unhealthy eating practices linked to eating disorders. These included fasting, using slimming drugs without medical supervision, vomiting after meals and taking laxatives.
They found that tanning bed usage was linked to an increase in these types of behaviours.
Associations were found in adolescent males and females, but the news tended to report the male figures as the links were stronger. In the previous year, more females reported using a sunbed than males (23.3% and 6.5% respectively) – an activity known to significantly increase the risk of the most dangerous form of skin cancer: melanoma.
Given the harmful effects of sunbed usage, efforts to better understand why people (particularly the young) use them, may help enact more effective prevention strategies.
If you are concerned that your teenage son or daughter is developing an unhealthy obsession about their appearance and weight, you should talk to them in a non-judgemental manner. Read more advice about eating disorders.
Where did the story come from?
The study was carried out by researchers from the New York University School of Medicine. No funding source was reported.
The study was published in the peer-reviewed Journal of Developmental and Behavioral Pediatrics, and has been made available on an open access basis, meaning it is free to read online or download.
Generally, the Metro reported the story accurately. The paper included a quote from one of the study's authors, Dr Michael Weitzman, who stated that “while the study can’t show a definitive link to eating disorders, it does suggest that teens who use indoor tanning have higher rates of unhealthy weight control behaviours linked to eating disorders”. This was an accurate assessment of the study’s findings.
What kind of research was this?
This was a cross-sectional study with the aim of discovering if “weight control behaviours” – such as fasting, vomiting or using laxatives to lose weight – were associated with tanning bed usage in young people.
The study noted that indoor tanning rates remain high among young people, despite the increased melanoma risk. The primary aim was to discover why people used tanning beds when they are known to increase the risk of cancer, with the belief that it could be due to negative body image and trying to “look good”. They indicated that little was known about the association between tanning bed usage and weight control behaviours in the young, particularly differences in young males and females, so undertook this latest research.
As this was a cross-sectional study, it cannot prove causation – that using tanning salons causes weight control behaviours. Such a link seems implausible, but it can highlight potential links between different behaviours.
This is potentially useful when assessing people at a high risk of eating disorders. Many factors would be considered, including body image and weight control behaviours. Additional measures such as sunbed usage could potentially add more to the picture, but may just be measuring the same thing.
What did the research involve?
The research used survey data from US high school students taking part in a Youth Risk Behaviour Survey (n=26,951) between 2009 and 2011. It aimed to discover links between indoor tanning usage in the previous year and doing the following to lose weight or prevent weight gain in the previous 30 days:
- fasting for more than 24 hours
- taking a slimming pill, powder or liquid without a doctor’s consent
- vomiting or taking a laxative
A number of potential confounders were adjusted, based on findings from previous research, including:
- self-perception of weight
- actual weight
- whether the person was trying to lose weight
- academic grade
- if they had felt sad or hopeless, or been bullied at school within the past 12 months
- if they had ever had sex, smoked or drunk alcohol, or drunk more than 5 alcoholic drinks in a row within the past 30 days
- whether they wore sunscreen (SPF15) when in the sun for over an hour
Out of 31,835 respondents, the researchers were able to use 85% (26,951) in their analysis of tanning and weight control behaviours. The rest had important data missing, so couldn’t be used.
The main analysis compared what weight control behaviours were significantly associated with tanning usage in males and females separately.
What were the basic results?
The summary results were as follows:
- within the past year, females had used indoor tanning a lot more than males (23.3% and 6.5% respectively)
- adjusted multivariate results showed females who indoor tanned were, on average, more likely to have fasted (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.0 to 1.5); taken a pill, powder or liquid (OR, 2.4; 95% CI, 1.9 to 3.0); and vomited or taken a laxative to lose weight (OR, 1.4; 95% CI, 1.1 to1.7) within the past 30 days than those who did not.
- males who indoor tanned within the past year were, on average, more likely to have fasted (OR, 2.3; 95% CI, 1.7 to 3.1), taken a pill, powder or liquid (OR, 4.4; 95% CI, 3.3 to 6.0), and vomited or taken a laxative to lose weight (OR, 7.1; 95% CI, 4.4 to 11.4) within the past 30 days
How did the researchers interpret the results?
The researchers’ said “significant associations between indoor tanning use and unhealthy weight control behaviours exist for both male and female adolescents, with a stronger association observed among males.[…] These results lend credence to prior hypotheses that concerns about a negative body image are a more likely cause for indoor tanning use than are positive ideals about body image (e.g. that tanned skin appears healthy). Understanding and addressing why these behaviours move in tandem are essential to improved policies and patient counselling strategies to help curb the rising melanoma epidemic”.
They added that “the association between unhealthy weight control behaviours and indoor tanning was even stronger among males merits comment. The population of males who indoor tan may, when compared to those females that do so, constitute a self-selected group of their same-sex peers at higher risk for victimisation, may be less risk-averse or less familiar with the potential risks of indoor tanning”.
This cross-sectional study can provide no firm conclusions, but suggests that unhealthy behaviours may cluster together. Specifically, that in young, American people, tanning bed usage in the previous 30 days was linked to a higher chance of fasting; taking a pill, powder or liquid; and vomiting or taking a laxative to lose weight or prevent weight gain. Over 70% of the participants sampled were between 15 and 17 years old.
Associations were found in young males and females, but the news tended to emphasise the male figures as the links were stronger.
The immediate implications of the findings are somewhat unclear. However, sunbed usage is known to significantly increase the risk of skin cancer, so efforts to better understand why people (particularly the young) use them, may help enact more effective prevention strategies.
The study makes tentative links between body weight, self-perception of body weight and indoor tanning usage, but provided little insight. Many argue that we live in an increasingly image-obsessed culture, so the study authors’ argument that their evidence warrants further investigation in a longitudinal cohort study, may ring true for many.
Analysis by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.