In this paper years of life lost were counted and analyzed by the method described by Christopher Murray and Alan Lopez in GBD 1990. It enabled us to compare the situation in Poland with other countries applying this methodology. It needs to be observed, however, that the 2010 Global Burden of Diseases, Injuries, and Risk Factors Study (GBD 2010) took into account certain epidemiological changes that occurred during the previous two decades and proposed certain modification in the methodology, which should be integrated in future research. Given the progress in extending life expectancy in the last 20 years, for the GBD 2010 study, it was decided to use the same reference standard for males and females and to use a life table based on the lowest observed death rate for each age group in countries of more than 5 million in population. The new GBD 2010 reference life table has a life expectancy at birth of 86.0 years for males and females. Taking into consideration many arguments for and against discounting future health and age-weighting in burden of disease measurement, it was decided that YLLs are computed with no discounting of future health and no age-weights [13].
The life lost years coefficients for the inhabitants of Poland decline systematically. In 1999, which is often selected as the point of departure for epidemiological analyses in Poland because of a major administrative reform of the country, the SEYLLp measure amounted to 73.9 per 1,000 inhabitants (97.3 per 1,000 males and 51.8 per 1000 females), which means they were higher than in 2011 by approximately 25%.
According to research conducted by Marshall, if years of life lost per death is calculated to be about 9–10 years, it is not out of the ordinary and means that the age at death is congruent to the model life tables for Western developed nations (MLTW) age structure [11,12]. The number of years of life lost amounted to 6.0 per single death in Poland in 2011, which is lower than norms. It is worth noting that while in Marshall’s studies there are only slight differences between men and women, this differential in Poland is quite substantial (7.1 per 1 dead man and 4.7 per one dead woman).
The structure of the three broad cause groups of the SEYLL measure within Poland resembles that seen in other European countries [14-17]. Diseases from Group II, i.e. chronic non-communicable diseases, undoubtedly contribute to the greatest number of lost years of life. Diseases from Group I, i.e. communicable diseases and maternal, perinatal and nutritional disorders, cause fewer lost years of life. The most visible differences can be observed in Group III, i.e. injuries. Of European countries, Poland and other Eastern and Central European countries,together with Finland, Portugal and France, experience the greatest number of years of lost life due to injuries [18]. Injuries caused 10.1%of total lost yearsof life in Spain and 5.3% in Germany,but as much as 16.0%in Poland. The difference which puts Poland in such a negative position is the high number of lost years of life experienced by males. The SEYLLp measure was 16.1 per 1,000 malesfor Poland compared with 7.3 per 1,000 malesfor Spain. Regarding women, the difference was much smaller: 2.9 per 1,000 females in Poland and 2.1 per 1,000 females in Spain.
A detailed analysis for the Lodz province, one of 16 provinces in Poland, confirmed that external causes of death, suicide in particular, represent a serious epidemiological problem, particularly for males. In 1999–2010, the number of years of life lost by males due to suicide systematically increased by 1.7% a year [19]. Although a decreasing tendency was observed in the death rate associated with the second most common factor, i.e. injuries, or traffic accidents, the rate still remains one of the highest in Europe. In 2011, higher SDR values were observed only in Romania, Greece and Latvia [8]. Traffic accidents contribute to the greatest number of deaths in people below the age of 25, which results in a great number of years of lost life. This loss of years mainly affects males, as 75% of people involved in traffic accidents are men. The widespread use of motor vehicles and motorbikescontributes to these statistics, especially those vehicles whose drivers often get involved in accidents, engage in drink-driving and exceed speed limits [19].
Of the Group II causes, non-communicable diseases, cardiovascular diseases and malignant neoplasms contribute to the greatest number of years of life lost, representing 42% and 37% of total years respectively. Since 1991, the position of cardiovascular diseases as the main cause of death in Poland has been systematically eroded [20,21]. Ischemic heart disease was found to have the greatest individual decrease as a cause of lost years in the Lodz Province [22]. However, it should be pointed out that the SEYLLp measure due to this cause is still the highest of all single disease entities in males and the second highest in females.
However, heart failure is characterized by a reverse trend. The number of years of life lost due to this cause is growing and in 2011, it was in 6th position for males and 3rd position for females in Lodz [22]. This implies a relationship between mortality due to ischemic heart disease and heart failure, with the latter being a final stage of cardiac damage, which itself is a consequence of various diseases. Progress in the treatment of acute coronary syndrome has improved prognosis in acute myocardial infarction, and significantly reduced mortality. However, although many people survive infarction, extensive cardiac damage gradually occurs which leads to heart failure. Paradoxically, improvements in diagnostics and treatment of cardiovascular diseases, particularly ischemic heart disease and arterial hypertension, lead to an increase in morbidity of cardiac failure.
In the group of malignant neoplasms, lung cancer contributes to a great number of years of life lost. Although in Poland, as can be seen in Western Europe, the incidence of lung cancer in men has been decreasing, a reverse trend can be observed for women [23-27]. Despite its diminishing tendency, the number years of life lost due to this cause is still very high in males, occupying 2nd position for single disease entities. For women, the trend has been systematically growing for some years, with the number of years of life lost in Poland in 2011 due to lung cancer (2.5 years per 1,000 females) being higher than the number of years of life lost due to breast cancer. Although nipple malignancies no longer occupy the first position, they nevertheless represent a serious life-threatening factor for females. Mortality due to nipple cancer is significantly more negative for younger women living in Poland than those living in other European countries [28], and forecasts indicate that it will increase over the forthcoming decades [29].
Regarding the remaining diseases in group II, liver cirrhosis is the third death cause leading to the highest number of life years lost per 1 person deceased due to a given cause. Mortality due liver cirrhosis is undoubtedly related to alcohol consumption. A Central Statistical Office study in 2009 showed that the average alcohol consumption calculated in pure alcohol amounted in Poland to 10.1 liters per person being 15 years old and more, which was slightly below the European average of 10.7 liters. However, the structure of alcohol consumption in Poland is unfavourable with above average consumption of strong alcohols and beer (respectively 3.76 l and 5.36 l) compared to the European Union (2.37 and 4.23 liters), while the consumption of wine in Poland (0.99 l) is one of the lowest all over Europe (where the average is 3.89 liters per person aged 15 and more [30]. In Spain, where the annual consumption of alcohol is higher than in Poland (11.4 liters), but win is much more important in the structure of alcohol consumption, SEYLLp coefficients due to liver cirrhosis amount to 1.6 per 1,000 males and 0.5 per 1,000 females, considerably less than in Poland [15].
Communicable diseases, as well as maternal, perinatal and nutritional disorders, contribute a relatively small number of years of life lost, both in Poland and in other developed European countries (5.3% of the total value of the SEYLL measure, with the SEYLLp equal to 3.1 per 1,000 inhabitants); in comparison, diseases from Group III contributed to 12.7% of lost years of life in Hong Kong, and the SEYLL measure was 11.8 per 1,000 inhabitants [31].
Limitations of the study
As the reliability of statistical analysis performed on the basis of deaths depends to the largest extent on the correct identification of the underlying cause of death, in particular among the elderly, certain changes were introduced in Poland in 2009. In order to standardize the recording of the cause of death, which are subject to further statistical analysis, it was determined that the doctor who states the death should be responsible for completing the death card with the underlying, secondary and direct causes of death, whereas qualified teams of doctors are responsible for coding these causes of death according to the ICD-10 classification. In addition, the duties of a dozen regional statistical offices were taken over by the Central Statistical Office of Poland. Unfortunately, the relatively short time that the new system of processing data on deaths has been operating prevents its evaluation. In future, it would be useful to compare the registered causes of death in the Central Statistical Office with actual medical documentation concerning the history of the disease in a randomly selected sample.
