Spatial Clustering of Scleroderma in Three Michigan Counties

1
Spatial Clustering of Scleroderma in Three
Michigan Counties
???? ???? ???? ???? ???? ????

• The Toledo Twins
• Sharon HensleyAlford
• Sarah Ann Cleveland

???? ???? ???? ???? ???? ????
2
?Background?

• The disease that turns people to stone
• Chronic, connective tissue disease
• Unknown cause
• Collagen accumulation in some organs
• Classifications
• Localized
• Systemic

3
?Who has scleroderma?

• Approximately 150,000 people in the United States
• 4 times more women than men

4
?Symptoms May Include?

• Raynauds Phenomenon
• Swelling of hands and feet
• Pain and stiffness of joints
• Thickening of the skin
• Kidney, heart, and lung involvement
• Oral, facial, and dental problems

5
?Diagnosis?

• Difficult
• Involvement of several specialists
• May take months to years

6
?Rates in Study Area?

• Prevalence
• 242 cases per 1million adults
• Incidence
• 19 new cases per 1 million adults per year
• Reference Prevalence, incidence and survival
  rates of systemic sclerosis in the Detroit
  metropolitan area. Mayes et al.

7
?Age Distribution of Cases?
8
?Sex Distribution?

• 134 Females
• 37 Males
• 3.62 times more females than males

9
?Etiologies?

• UNKNOWN
• Possibilities include
• silica dust
• vinyl chloride monomer
• pet ownership
• some solvents
• appetite suppressants

10
?Significance?

• To Explore...
• Environmental associations
• Spatial pattern ? Disease process

11
?Materials?

• Disease Data
• Incidence data for 1989-1991 (N171)
• Three counties
• Macomb
• Oakland
• Wayne

• Population Data
• 1990 Census data
• Block and Tract divisions

12
?Methods?

• Gathering population data
• Finding census data
• Extract pertinent information
• Geocoding cases
• ArcView Batch Match
• Digitizing unmatched cases

13
? Working with Unmatched Cases ?

• Verifying address US Post www.usps.gov
• Using web map programs
• Mapquest www.mapquest.com
• gives county lines
• Vicinity www.mablast.com
• Digitizing

14
?Matching Rate?
171 Original
5 Unmatchable Addresses n166
161 Matched/166 Total 96 Matching Rate
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
?Statistical Analysis?

• Null Hypothesis No spatial clustering
• Alter. Hypothesis Spatial clustering
• Test statistic Ipop, Morans I
• Statistical Program STAT!

19
?Macomb/Tracts?

• Assumption R
• Variance 0.0000000
• z-score -0.3175953
• Significance 0.7507920 (2-tailed)
• Approximation
• Variance 0.0000000
• z-score -0.3121641
• Significance 0.7549158 (2-tailed)
• Simulation
• Significance 0.8800000 (2-tailed)

• STAT Output 4/13/1999
• Results from Ipop test
• Number of runs 99
• Ipop calculations
• Areas (m) 194
• cases (n) 30
• Population (x) 724110
• Ipop -0.0000099
• Ipop' -0.2377846
• EI -0.0000014
• within 99.9752702
• among 0.0247298

20
?Macomb/Block?

• STAT Output 4/14/1999
• Results from Ipop test
• Number of runs 99
• Ipop calculations
• Areas (m) 661
• cases (n) 30
• Population (x) 724112
• Ipop -0.0000208
• Ipop' -0.5008514
• EI -0.0000014
• within 99.9957345
• among 0.0042655

• Assumption R
• Variance 0.0000000
• z-score -0.3930764
• Significance 0.6942630 (2-tailed)
• Approximation
• Variance 0.0000000
• z-score -0.3855452
• Significance 0.6998335 (2-tailed)
• Simulation
• Significance 0.6400000 (2-tailed)

21
?Oakland/Tracts?

• STAT Output 4/13/1999
• Results from Ipop test
• Number of runs 99
• Ipop calculations
• Population (x) 1101540
• Ipop 0.0000033
• Ipop' 0.0817093
• EI -0.0000009
• within 99.8772695
• among 0.1227305

• Assumption R
• Variance 0.0000000
• z-score 0.2045747
• Significance 0.8379044 (2-tailed)
• Approximation
• Variance 0.0000000
• z-score 0.2022084
• Significance 0.8397538 (2-tailed)
• Simulation
• Significance 0.5600000 (2-tailed)

22
?Oakland/Blocks?
23
?Wayne/Tracts?

• STAT Output 4/13/1999
• Results from Ipop test
• Number of runs 99
• Ipop calculations
• Areas (m) 632
• cases (n) 86
• Population (x) 2159815
• Ipop -0.0000062
• Ipop' -0.1565116
• EI -0.0000005
• within 100.4700628
• among -0.4700628

• Assumption R
• Variance 0.0000000
• z-score -0.3578355
• Significance 0.7204664 (2-tailed)
• Approximation
• Variance 0.0000000
• z-score -0.3542334
• Significance 0.7231640 (2-tailed)
• Simulation
• Significance 0.9200000 (2-tailed)

24
?Wayne/Blocks?
25
?Discussion?

• Limitations of Analysis
• Position uncertainty
• Residential history
• Reliability of census data
• Future Analysis
• Stratification by age, sex, race
• 3 county combination analysis
• Space/Time Analysis

26
?Thank You?

• First Honors Andy Long
• Mark Wilson
• Dr. Mayes
• Geoff Jacquez