cases from greenland were retrieved from the national patient register , in which all admissions to hospitals in the entire greenland are registered , using icd-10 code c25 . multiple registrations of a same patient were removed , including only the first duplicate record . cases from denmark were retrieved from the cancer register , in which all diagnoses of cancer in denmark are registered . however , only the number of cases in each year and 5-year age group was available . country - specific population data for greenland and denmark were collected from the national statistical databases , www.stat.gl and www.dst.dk , respectively . age - specific rates ( ir ) for each age group were retrieved using the country - specific population in the age groups as person years at risk . to compare the rates , a method of indirect standardization was used , as the intention of the study was to compare only 2 population groups . to obtain the expected number of cases in the greenlandic population , if the 2 countries had the same population age distribution , danish age - specific rates were applied to the greenlandic demography and summed to yield an overall standardized incidence rate expressed as per 100,000 inhabitants . a ratio ( sir ) of age - adjusted rates was used to compare greenland rates with those of denmark . as the number of observed cases in greenland was relatively small ( in average 10 per year ) 95% confidence intervals ( cis ) were calculated under the assumption that the cases followed a poisson distribution . in denmark , a total of 9,388 cases were observed in the period 20002010 , whereas the corresponding number in greenland was 109 cases . inuit were significantly younger than danes ( mean 62.79.9 vs. 70.011.2 ; p<0.0001 ) at the time of diagnosis . ten percent of inuit cases were observed before the age of 50 , whereas in denmark 5% of the cases were observed before the age of 50 . age distribution of cases at the time of diagnosis 
 table ii shows the danish and greenlandic crude rates compared with the age - adjusted sir . the p - value indicates the level of significance of the sir for greenland compared with denmark . the crude rates ( ir ) and age - adjusted ( sir ) ratios per 100,000 inhabitants for greenland compared with denmark year of diagnosis a weighted average of the sir for the years 20002010 yielded a sir of 2.38 ( 95% ci : 1.972.86 ; p < 0.0001 ) . a linear regression analysis showed no significant changes over the 11-year period ( p for trend : 0.25 ) indicating that the sir between the 2 countries has not changed since 2000 . furthermore , a linear regression analysis of the rates in greenland  after being standardized according to the danish rates  showed no significant changes ( p for trend : 0.8 ) . this study revealed a sir of 2.38 ( 95% ci : 1.972.86 ; p<0.0001 ) for greenland compared to denmark for the period 20002010 . this ratio has been constant throughout the entire observation period ( p for trend : 0.25 ) . the sir corresponds to the result found by friborg et al . in 2003 ( 9 ) . this fact combined with the p - value for trend ( 0.25 ) indicates that the relative incidence rate of pc in greenland compared with denmark has been constant since 1988 . furthermore , we found the absolute incidence rate in greenland to be constant in the period 20002010 as well ( p for trend : 0.8 ) . the effect of tobacco smoking on pc is well documented and as much as 25% of pc the prevalence of daily smokers in the adult greenlandic population is 66% ( and decreasing ) ( 18 ) , while this number in denmark is 21% ( 19 ) and could account , in part , to the higher rates of pc among the greenlandic population . as an effect of the decreasing use of tobacco smoking in both countries ( 18,20 ) , it is likely that a lower number of smoking - related pc will be observed in future years . however , the cessation of tobacco smoking will have to last for at least 10 years , before a reduced risk will be present ( 15 ) . diabetics are known to have 1.52 fold higher risk of developing pc than have the non - diabetics ( 21,22 ) . in 2009 , 28% of the greenlandic population aged over 65 years had dm-2  an increase from 10% in comparison with 1999 ( 23 ) . in denmark , 6% of the population more than 60 years had dm-2 in 1999 increasing to 14% in 2009 ( 24 ) . thus , the prevalence of dm-2 is twice as high in greenland as in denmark and could also account for some part of the findings in this study . after the time of the diagnosis , dm-2 may increase the risk of pc ( 21 ) , although increases in dm-2 during 19992009 did not result in increases in pc during 20002010 . tobacco smoking has for a long time been a part of the greenlandic culture , but the tendency to smoke is decreasing , probably because of higher price and better educational levels ( 25 ) . the higher prevalence of dm-2 in greenland compared with denmark is probably associated with the westernization mentioned in the introduction section . the transition in lifestyle has led to obesity , lack of physical activity and unhealthy diet , thus increasing the risk of acquiring dm-2 . a factor less probable to be of significant contribution to our findings is chronic pancreatitis . though expected to increase the risk of pc ( 26,27 ) , a study by tramacere et al . ( 28 ) has shown that only 5% of all cases of pc can be related to chronic pancreatitis . furthermore , algul et al . ( 6 ) found that 7080% of all cases of chronic pancreatitis is due to alcohol . alcohol per se is probably not a risk factor , but an excessive daily intake of alcohol may lead to pancreatitis and thereby to pc ( 28 ) . in denmark , the average yearly intake per person is 11.3 l of alcohol ( 29 ) corresponding to the greenlandic value of 11.7 l ( 30 ) . the significantly increased risk of pc in greenland found in this study is therefore not likely to be explained by a difference in alcohol intake . the consumption of alcohol has been decreasing in greenland ( since 1988 ) , and it is possible that the incidence of pc will decrease as a long - term effect of this change of lifestyle . however , as the drinking patterns ( binge drinking vs. alcoholism and intake among young vs. elderly people ) in the 2 populations are not necessarily comparable and data on chronic pancreatitis are currently not available , it is very difficult to examine the influence of alcohol to the findings of this study . it is not known how many of the observed cases that can be related to hereditary syndromes such as hnpcc and peutz  jeghers , but we know that hereditary pc tends to debut at a younger age ( 31 ) . as the greenlandic cases tended to be younger than the danish cases ( however , the age at diagnosis for the danish cases is an approximation as the data on the exact ages were not available ) , and that twice as many cases in greenland than in denmark were below the age of 50 , a genetic component can not be disregarded and should be subjected to further investigations . also , possible risk factors including infection with microorganism helicobacter pylori , liver cirrhosis through alcohol consumption and occupational exposures could all lead to an increase in the incidence of pc ( 3234 ) . combinations of more or all of the risk factors mentioned in this article are very likely in greenland , thus increasing the risk of pc . the results from greenland are associated with a certain degree of uncertainty due to the low number of observations ( a total of 109 cases ) , though making the greenlandic rates very vulnerable to smaller changes in the incidence . the cancer registry in denmark has in earlier studies shown to be very reliable ( 35 ) . this should to some extent rule out the possibility of people having pc without being diagnosed . however , in sparsely populated areas of greenland , people could have died of pc without being diagnosed . this is probably not likely in denmark , as pc is an aggressive malignancy and cases of pc misclassified as chronic pancreatitis would quickly be apparent . any case of a non - diagnosed pc in greenland ( where it would be more likely than in denmark ) would support the findings , as well as if there were multiple entries of the same patient in the danish registries thus lowering the actual danish ir . none of these registrations were found in the greenlandic data , whereas the incidence of endocrine pancreatic tumours in denmark was unknown . if endocrine tumours of the pancreas had been registered in the danish population , our estimate would have been biased towards the null - hypothesis of no difference . in that case , the sir is underestimated . in summary , the findings of this study suggest a significantly increased incidence of pc in greenland compared with that in denmark . this could be related to a higher prevalence of tobacco smoking and dm-2 in the greenlandic population . also , the study showed that there has been no change in the incidence ratio for greenland compared with denmark for the last 2 decades . to lower the incidence of pc in greenland , prophylactic measures against these lifestyle factors however , a genetic impact can not be disregarded and should be subjected to further investigations .
backgroundinuit people are known to be at an increased risk of cancers usually uncommon to the western world such as cancers of the nasopharynx and salivary glands . but what is the trend regarding pancreatic cancer?objectiveto determine the incidence of pancreatic cancer ( pc ) in greenland compared with denmark in the period 20002010.study designretrospective register - based study . 
 cases were retrieved from the danish cancer register and the greenlandic patient register and stratified in 5-year age intervals for each year . 
 age - standardized incidence ratios ( sir ) for each year for greenland compared with denmark were calculated using the number of cases and the number of inhabitants in each 5-year age interval and in each country . 
 the average sir for the entire period was calculated using a weighted average.resultsthe study revealed a sir of 2.38 ( 95% ci : 1.972.86 ; p<0.0001 ) indicating a significantly increased incidence of pc in greenland compared with denmark . 
 a linear regression analysis showed no significant change in the sir over time ( p for trend 0.25 ) as well as no significant change isolated in greenland ( p for trend 0.8 ) . 
 furthermore , the inuit were significantly younger at the time of diagnosis ( mean 62.7 vs. 70.0 ; p<0.0001).conclusionsthe age - standardized incidence of pc is 138% higher in greenland than in denmark . 
 a part of this could be explained by a higher prevalence of smoking and dm-2 . 
 however , the impact of genetic factors can not be disregarded and should be subjected to further investigation .