text: ***4.2.2 Attributable fractions, risk pairs and burden of disease***
  As mentioned, for the**majority of diseases the working conditions are one of several influence**
  **factors**in combination with other factors like private life, social and medical system, genetics, 
  environment and so on. The exact impact of this factor, that is, the fraction of disease generating or 
  intensifying impact**attributable to work**, is the subject of numerous studies in occupational 
  epidemiology.210 
  
  The overall relation between work and illnesses is moving towards**a less unambiguous picture**
  compared to occupational diseases, where a strong relation between a single (over-)exposure and a 
  specific illness existed. These were mostly high exposure levels that could not be found outside 
  workplaces. Obviously, many such high exposures still exist and are important for prevention and 
  compensation. However, many exposures at work approximate to other non-work exposures, like 
  permanent sedentary work. This makes it more difficult to separate unambiguously the impact of work. 
  
  Science, in particular occupational epidemiology, and institutions like the ILO and WHO studies have 
  engaged to identify the approximate impact of work for diseases, the**attributable fraction of work**. 
  
  For example, the**WHO**summarised their estimates in the year 2017: 
  
  *‘Certain occupational risks, such as injuries, noise, carcinogenic agents, airborne particles and*
  *ergonomic risks account for a substantial part of the burden of chronic diseases: 37% of all cases of*
  *back pain, 16% of hearing loss, 13% of chronic obstructive pulmonary disease, 11% of asthma, 8% of*
  *injuries, 9% of lung cancer, 2% of leukaemia and 8% of depression.’*211 