1. Although mortality due to influenza (as a registered underlying cause of death) forms only 8% of this mortality increase, it is well known that influenza also contributes to the death of people with other underlying conditions, especially chronic cardiovascular and respiratory diseases. Analyses from the United Kingdom have shown that each influenza death was associated with 3 6 excess deaths (due to all causes including influenza) in 1949-1985.'4 There appears to have been a rise in the total number of excess deaths per influenza death over this period, and during a recent epidemic in the winter of 1989/1990 a ratio of 10: 1 was found.'5 On the basis of table IV we would calculate a ratio of
2. Long term trends in seasonal mortality;McDowall, M.;Popul Trends,1981
3. Use of Poisson regression model in estimating incidence rates and ratios;Frome, E.L.; Checkoway, H.;Am Jf Epidmiol,1985
4. Circular statistics in biology;Batschelet, E.,1981
5. GLIM manual (release 3);Baker, R.J.; Nelder, J.A.,1987