LAUSR

There is an ongoing shift in the age distribution of bariatric patients. This assumption was confirmed in a large bariatric center with a retrospective analysis of primary operations. Before 2008, 28% of the patients were above 45 years old (Fig. 1). This portion increased to a current 50%. In order to explain this trend, the demographic data of the Netherlands were reviewed using a nationwide registry for demographic data. After WWII, there was a major increase in birthrate until it peaks around 1970 [1]. Thereafter, the annual number of births is steadily declining. This leads to an overrepresentation of patients above 45 years of age, the so-called baby boom generation. Furthermore, the life expectancy has increased considerably. The life expectancy of newborns in 1960 was around 73 years and is 82 years nowadays [2]. So, in other words, there are relatively more older people and these people are getting older. This Bdouble-graying^ of people is reflected by the nationwide registry: in 2007, 41% people where 45 years or older, while nowadays this has increased to 47% and is expected to increase even more in the coming decades [3]. The prevalence of obesity is increasing in every age group in the Netherlands [4]. There is a 2.5% increase in occurrence of overweight (body-mass index above 30 kg/m) between 2007 and 2017, from 9.8 to 12.3%. This growing trend is seen across every age group, but is more striking in older patients. For instance, the prevalence of overweight in patients between 50 and 55 years old increased from 14 to 18.4%. In addition, the prevalence of obesity was already higher in older patients. Consequently, this is leading to a rapid climb in absolute number of overweight older patients. The combination of increased life expectancy and increase in obesity could result intomore years with co-morbidities due to the metabolic syndrome. For this group, a lesser minimum of obesity can be enough for indicating a procedure. This is why bariatric surgery shifted towards a metabolic disease treatment. It seems logical that the effects of metabolic syndrome over time gives more damage to end organs, such as kidney failure and cardiac failure, so the older patient is at a higher risk. This effect can be called Bthe fat-years,^ similar to the term Bpack-years^ which describes the cumulative exposure to smoking and is correlated with increased risk of lung