Download Medical Cartography & Spatial Analysis Lecture Slides and more Slides Medicine in PDF only on Docsity! Lecture 10: Medical Cartography / Spatial Analysis Overview • DEGENERATIVE DISEASES – Importance Of Degenerative Diseases – Underlying Rationale Of Spatial Analysis • MEDICAL CARTOGRAPHY • SPATIAL ANALYTICAL METHODOLOGY – Significance – Indices – Indicators of Significance • EXAMPLES Degenerative Diseases • Following the decline in infectious diseases, the three major degenerative diseases (heart disease, cancer and stroke) account for 2/3 of all deaths. Many of the remaining 1/3 are triggered by degenerative complaints. • The key questions are: – Are the disparities between areas in disease rates simply due to chance or caused by something? – If they are caused by something, can we identify what the something is? – Having identified a cause, can we do anything to prevent it? • The first question involves mapping diseases and testing for statistical significance.
lee
50 Q a 50 100
DW Districes attacked by cholera in 183:-1233
(Shoding is darker in proportion to relotive
‘mount of mortality)
Fig. 4. Augustus Petermann’s cholera map (1852) of the British Isles showing
areas affected in 1831-3
WooDHouse Yards
cana se gO toe
WD Districts offected by cholera
NETHER
GREEN
|
GREAT
WOODHOUSE
HUNSLET
Fig. 2. Dr. Robert Baker's “cholera plan” of Leeds (1833)
CHOLERA
Yords
“ge. o 100 200 300 ago BuaviNne
cRounn
Deoths in 1832 *, 1833 », 1834 0
12. Where clothes were destroyed
3Soup kitchens 4.5.6.7. Druggists
DAWES
th casree or?
euoeeas *% couwrr
BURYING So cack
city
warxwouse .
Fig. 3. Dr. Thomas Shapter's map (1849) of the deaths from cholera in Exeter
1832-34 :
Fig. 11, H. W. Acland’s map of undrained districts in Oxford 1854 (1856)
Yards
50 ° 50 ne 2 00
x Pump e Deaths from cholere
"ig. I. _Dr. John Snow's map (1855) of deaths from cholera in the Broad Street
area of London in September 1854 |
Spatial Analytical Methodology • Meaning of significance. Unlikely to have occurred by chance, therefore something must be causing it. • Indices. Crude death rates / crude morbidity rates can be very misleading. Need to calculate age specific or age standardised rates. • Indications of spatial significance: extreme variations between areas; spatial autocorrelation (clustering); temporal consistency. • Hypothesis testing. If the distributions of a disease is found to be significant, then the objective is to identify possible causes – i.e. factors having a similar spatial distribution.
[J] 70-73 |
[_] 700-709
[7] 690-699
680-689
Hl 676-679
Life expectancies at birth
Regional Variations In Ireland • Mortality rates are higher in urban areas (and urbanised counties). • The regional pattern in Ireland was unusual in the 1970s because the more deprived regions tended to have lower mortality rates. • The regional anomalies appear to be breaking down in the 1990s.
oonens
Saessegage
ee
ALL CAUSES, 1971-90
Females Aged Less Than 76
1
£O56SR868
mn
ALL CAUSES, 1971-30
Males Aged Less Than 75
STANDARDISED
MORTALITY RATIOS
im
>120
110-120
100-110
90-100
80-90
<80
MALIGNANT NEOPLASMS
STANDARDISED
MORTALITY RATIOS
Bn
110-120
ll 100-110
—
— 90-100
80-90
<80
RESPIRATORY DISEASES
STANDARDISED
MORTALITY RATIOS
>120
110-120
100-110
90-100
80-90
<80
