Congestiones vehiculares y tiempos de viaje

After the Second World War the incidence rate of hip fractures increased almost exponentially in the western and north European countries. This of course caused great concern regarding future developments in terms of future burden on the health care system. Several authors have attempted to predict the future burden based on the drastic increases seen in the incidence rate of hip fractures during the 70’ies and 80’ies. Most studies have been based on local and regional developments of the hip fracture incidence rate. A few have attempted to predict the future burden of hip fractures on a global level, based on incidence reports from local studies around the world. Key point is shown in the following.

4.10.1 Danish studies

Frandsen et al [1] predicted the number of hip fractures for Funen County in 1985, 1990, and 1995, based on incidence rates from 1973 to 1979. Frandsen expected the number of incident hip fractures for Funen County for the year 1995 would increase to 143-375 in men and 524-1123 in women, depending on the model applied.

From 1979 to 1995 one model predicted an increase in the number of incident hip fractures of 10%, whereas another predicted an increase of 150%.

From the hospital in Aalborg Rasmussen [3] used the number of hip fractures reported to the NPR for the period 1976 to 1988 to predict the future number of hip fracture until the year 2010. A linear regression model as well as a semi logarithmic model was applied. By the linear model the number of fractures was expected to increase from 344 in 1988 to 794 in 2010, the incidence rate was ex-

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pected to increase from 7.15 per 1,000 py in 1988 to 14.5 per 1,000 py in 2010. Using the semi logarithmic model the number would increase to 825 hip fractures, and the incidence would in- crease to 15.9 per 1,000 py.

Based on all incident hip fractures occurring in Aarhus municipality during 1970 to 1986 Schroder et al [2] applied two models for the projection of hip fractures. The observed age specific incidence rate from 1986 was applied to the population forecast, predicting a 19% increase in the year 2002. The second model applied the observed increase in the age specific incidence during the period and was then extrapolated by log linear regression. This model suggested a 91% increase by the year 2002.

4.10.2 International studies

In New Zealand Rockwood et al [72] applied the age specific incidence rates of 1987 onto the pro- jected population as well as a weighted regression analysis based on the development in age spe- cific incidence rates from 1968 to 1987. All hip fractures reported to the national health register were included. Model one predicted an increase in the number hip fractures among women from 2,000 to 3,500 in 2011. The weighted regression was nearly the same. In men the weighted regres- sion showed a significant increase in the expected number of hip fractures, from 549 fractures in 1987 to 1,300 in 2011. The increase was based on not only the expected population dynamics but also as a result of increasing age specific hip fracture incidence among men.

Nilsson et al [9] estimated first hip fracture incidence rates for the period 1970 to 1985. They then applied two models of projection: 1) the age and sex specific incidence of 1985 would be projected onto the population forecast, 2) the change in age and sex specific incidence from 1970 to 1985 would continue and be projected onto the population forecast. The total number of fractures would increase from 680 in 1986 to 1106 by the year 2000, a 66% increase. Of these 56% would depend on the changed incidence rate, and 44% of the increased number of people.

Jaglal et al [73] based future hip fracture projections on age and sex specific incidence figures from 1981 to 1992 from Ontario, Canada. The incidence rates were estimated from all patients dis- charged with a diagnosis of hip fracture. By the year 2010 the number of hip fractures would double from 8,490 in 1990 to 16,963.

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Papadimitropoulos et al [74] projected the number of hip fractures for Canada by applying the inci- dence rate of 1993-1994 onto the population forecast to 2041. The total number of fractures were estimated to increase from 23,375 in 1993-94 to 88,124 (range 78,649 – 103,954) in 2041.

From Finland Kannus et al [20] used incidence rates of the first hip fracture during 1970 to 1997 to predict the number of first hip fractures until 2030. They applied the age and sex specific as well as the overall incidence rate onto the forecasted population. The predicted number would then treble by the year 2030.

From 1989 to 1996 Chipchase et al [75] found an almost unchanged incidence rate of hip fractures in South Australia, and therefore projected the age and sex specific rate of 1996 onto 2051. The number of hip fractures would be expected to increase from 1633 to 2714 in 2021 and 4730 in 2051.

Löfman et al [76] repeated the study by Nilsson et al [9] as the incidence rate of the area had changed compared to the previous study. Three models were used to estimate the future number of hip fractures. 1) The change in age and sex specific incidence from 1982 to 1996 was projected. 2) The change in age and sex specific incidence from 1970 to 1996 was projected. 3) The mean age and sex specific incidence from 1994 to 1996 were projected. Model 1 resulted in an overall de- crease of 11% in the number of fractures. Model 2 resulted in an increase of 11% in 2010. Model 3 showed a slight decrease.

Based on available age and sex specific hip fracture incidence rates from around the world and the projected populations in 1990, 2025 and 2050 Cooper et al [77] estimated the number of hip frac- tures that might occur in each of the major continental regions. An estimated 1.66 million hip frac- tures occurred in 1990 throughout the world. This number would increase to 3.94 million in 2025 and 6.26 million in 2050. While one third of all hip fractures in women in 1990 occurred in Europe or Asia, the demographic changes would result in over half of all female hip fractures occurring in Asia by 2050. In 1990 half of all hip fractures occurred in North America and Europe, by 2050 this would decrease to 25% with a steep increase in Latin America and Asia.

Gullberg et al [78] also projected the worldwide number of hip fractures. They estimated the num- ber of hip fractures in 1990 to 1.26 million. Assuming no change in age and sex specific incidence,

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the number of hip fractures was estimated to increase to 2.6 million in 2025 and 4.5 million in 2050. However if the trends in age and sex specific incidence from the regions were applied this number could range from 7.3 to 21.3 million by 2050, with the most dramatic increase in Asia.