Occupation and Mortality.—To obtain correct statistics showing the influence of occupation on vitality, one must know the number and age of those engaged in each industry, and the corresponding number of deaths. A statement of the mean age at death of those engaged in different occupations would be most fallacious (page [344]). The best plan is to restrict the statistics to men aged 25-65, and calculate for these death-rates in a standard population, after the fashion already described (page [340]). By this means a “comparative mortality figure” can be obtained. For all males it is 1000, for farmers 563, teachers 603, lawyers 821, doctors 966, butchers 1096, plumbers 1120, brewers 1427, innkeepers 1659, potters 1706, file-makers 1810. Speaking generally, the occupations are most unhealthy in which there is most exposure to dust, to the breathing of foul air, and to excessive indulgence in alcoholic drinks (for further details see the author’s Elements of Vital Statistics, page [169] et seq.).
Deaths from Various Causes.—These may be stated in proportion to total deaths from all causes, or in terms of the population. The first plan must be adopted only when it is desired to ascertain the proportional share of a given cause of death in the total mortality. In 1899, in England and Wales the diseases named in the first column of the table (page [344]), were the most prolific causes of deaths.
England and Wales, 1899.
Deaths from Various Causes to 10,000 Deaths from all Causes.
| Bronchitis | 880 |
| Phthisis | 729 |
| Pneumonia | 685 |
| Old age | 541 |
| Diarrhœa, Dysentery | 511 |
| Cancer | 452 |
| Apoplexy | 327 |
| Influenza | 213 |
| Whooping cough | 174 |
| Measles | 172 |
| Diphtheria | 160 |
| Enteric fever | 108 |
| Scarlet fever | 64 |
| Small-pox | 3 |
The diseases in the second column are given in order to indicate their proportional share of the total number of deaths.
The proper plan of stating the death-rate from a given disease is in terms of the population, or better still subdivided into death-rates from the disease for different age-groups as in the table on page [340], if the number of deaths is not too small to admit of this. The importance of stating the death-rate for different age-groups is greatest for such diseases as diarrhœa, whooping cough, and measles, in which most of the deaths occur at ages under five. In the following table are given the death-rates from the causes of death which are most important, either from their magnitude, or because of their preventible character:—
England and Wales, 1899.—Death-rate per 1,000 Persons living.
| Small-pox | ·005 |
| Measles | ·32 |
| Scarlet fever | ·12 |
| Influenza | ·39 |
| Whooping cough | ·32 |
| Diphtheria | ·29 |
| Enteric fever | ·20 |
| Typhus fever | ·001 |
| Cholera | ·04 |
| Diarrhœa, Dysentery | ·94 |
| Intemperance | ·09[14] |
| Cancer | ·83 |
| Phthisis | 1·34 |
| Other tubercular diseases | ·58 |
| Premature birth | ·58 |
| Old age | ·99 |
| Apoplexy | ·60 |
| Convulsions | ·57 |
| Valvular disease of heart | ·38 |
| Bronchitis | 1·61 |
| Pneumonia | 1·26 |
| Gastro-enteritis | ·61 |
| Bright’s disease | ·29 |
| Accidents | ·59 |
| Ill defined and not specified causes | ·73 |
| ———— | |
| All causes | 18·33 |
Determination of Longevity. We have hitherto considered only death-rates, i.e. the number dying each year out of each 1,000 of population. The mean duration of life involves another aspect of the same problem. Although nothing is more uncertain than the duration of individual life, the duration of life for the entire community is subject to so little variation that annuities and life assurance can be made the subject of exact calculations. Of the tests employed to measure the duration of human life the most commonly employed is the mean age at death.[15]
sum of ages at death.
Mean age at death = ——————————
number of deaths.