Forty-one men and 51 women diagnosed with PD were compared to
controls (47 men and 63 women). Average age was 70.55 for PD patients
and 68.38 for controls. Present age of subjects with PD (n = 92) ranged
from 55 to 78, while controls (n = 110) ranged from 55 to 79. In the
group of subjects, 5 individuals were brown and 5 black-skinned; among
controls, 12 were brown and 7 were black.
history: Among subjects, 20.65% (17/92) had a family history of PD.
Regarding distribution of relatives affected by the disease, it was
found that first degree relatives were associated to 12 cases, second
degree relatives were observed in 5 cases, and third degree relatives
appeared in 4 cases. Only two controls had a family history of PD.
Herbicides and pesticides: From the total of selected individuals for
this factor, 6 were diagnosed with PD (6.36%) compared with 3 controls
(2.72%). Among the cases where contact with these compounds was
reported, 4 individuals had used them during rural residency (all had
PD), while the remaining ones had used them in their own houses.
C) Chemical agents: 14 subjects and 4 controls were included. Table 1 shows the chemical products involved. Occupations were: painters, dentists, goldsmiths and car mechanics.
D) Drugs: this variable was present in 22 cases of PD (23.9%); 5.43% of
subjects reported not having any perception of parkinsonian symptoms
while using mentioned drugs. Four controls (3.63%) with a history
associated to the use of parkinsonian drugs were noted. Table 2 shows distribution of drugs involved among subjects and controls.
E) Trauma: 17 subjects (18.5%) had some relevant history of head trauma, compared with 14 controls (12.7%).
F) Rural living: 26 subjects (28.3%) and 31 controls (28.2%) matched necessary criteria for this variable.
G) Potable water well-source: 26 subjects (28.3%) and 23 controls (20.9%) had a history of well-water intake.
H) Cigarette smoking: 9 subjects (9.8%) and 24 controls (21.8%) were cigarette smokers.
1) Univariate analysis: Table 3
displays results. This method demonstrated that the considered risk
factors for the disease were distributed by odd terms as follows:
family history 14.05 (CI = 2.98 - 91.38), drugs 11.01 (CI = 3.41 -
39.41), chemical agents 5.87 (CI = 1.48 - 27.23), and cigarette smoking
0.39 (CI = 0.16 - 0.95). The obtained confidence intervals for drugs,
chemical agents and family history were considered as inaccurate.
2) Stratified analysis: Drugs and family history variables were
confirmed as risk factors, while cigarette smoking was considered a
protection factor. Results obtained were: 1 ¾ PD association to the use of drugs presented variations in relation to the odds ratio for the drugs variable (Table 4).
Its value of 11.01 (CI = 3.41 - 39.41) underwent the following
variations: a) If analyzed among smokers it falls to 6.57 (CI = 0.36 -
221.95); b) Among non-smokers it becomes stable at 11.93 (CI = 3.18 -
52.79). 2 ¾ PD associated to
family history indicated that the odds ratio value that was 11.5 (CI =
0.98 - 356.91) among smokers rose to 20.3 (CI = 2.68 - 427.95) among
non-smokers. 3 ¾ Cigarette consumption odds ratio underwent the following alterations in relation to use of drugs (Table 5):
a) If analyzed among those that made use of drugs, its value is 0.24
(CI = 0.01 - 9.17); b) Among those who did not make any use of drugs,
the value is 0.44 (CI = 0.16 - 1.17).
3) Multivariate analysis: This process used the logistic
regression method, where values pertaining to the parameters' estimates
(PE), X2 test (chi-square), are presented together with the
significance level. Methodology applied considered significance level
(SL) equivalent to a probability of 5% (p < 0.05). In order of
decreasing importance, factors bearing significant values for PD were:
drugs (SL = 0.0001; X2 = 27.58; PE = 2.973), family history (SL =
0.0006; X2 = 4.4; PE = 2.733) and chemical agents (SL = 0.0014; X2 =
10.19; PE = 2.214). No significant values were found associated to
rural residency (SL = 0.138; X2 = 2.2; PE = - 1.26), well water (SL =
0.211; X2 = 1.56; PE = 1.12), herbicides and pesticides (SL = 0.271; X2
= 1.21; PE = 0.887) and trauma (SL = 0.887; X2 = 0.02; PE = 0.067).