Page 30 - Revista Portuguesa - SPORL - Vol 62. Nº1

Introduction from January 1 to December 31, 2021, were
Vertigo and dizziness affect around 20–40% of
the general population and are among the most
common medical complaints in emergency
rooms. Benign paroxysmal positional vertigo
1
(BPPV) is the most common type of vertigo.
2
The reported incidence of BPPV is 0.6% per
year and the lifetime prevalence is 2.4% of the
population. In BPPV, detached otoconial debris
3
from the utricular macula moves around in the
semicircular canal or attaches to the ampullary
cupula, which causes recurrent vertigo induced
by positional changes of the head. Those
3
symptoms are associated with a considerable
personal and health care burden, as they
generally require medical consultations and lead
to disruption of daily activities and absenteeism. 4
Although most commonly BPPV is idiopathic,
it maybe also be secondary to head trauma,
Ménière’s disease, or Vestibular Neuritis. Age
5
and gender has been reported as risk factors for
BPPV. BPPV is more common in individuals in
their 50s and 60s, and the rate of occurrence is 2:1
to 3:1 in women and men. Seasonal variation
3,6
in BPPV has been evaluated in several studies
with diverging results. While some studies
found indications of seasonal variation , other
7
studies did not confirm these findings. In
8
a tropical region study, vertigo was more
frequent in late winter–spring, negatively
correlating to humidity and rainfall. According
9
to an earlier study, the incidence of BPPV
was associated with monthly changes in air
temperature and pressure. In a large study of
10
the German population, no seasonal variation
was demonstrated for any vestibular disorder. 8
Considering the scarce and conflicting reports
on the subject, this study aimed at analyze the
existence of a seasonal distribution of BPPV,
and the correlations of these findings with
climatic factors.
Material and Methods
Data collection
Patients who visited the emergency room of
Centro Hospitalar Universitário Lisboa Central
(latitude: 38.7177640, 38°43’04.0”N; longitude:
-9.1374533, 9°08'14.8"W) with vestibular symptoms
30 Revista Portuguesa de Otorrinolaringologia - Cirurgia de Cabeça e Pescoço
enrolled in the study. The diagnosis of BPPV was
confirmed by symptoms consistent with BPPV
as well as typical nystagmus during diagnosis
maneuvers. Proper canalith-repositioning
maneuvers were performed according to the
affected canal. Secondary BPPV patients who
have specific causes for BPPV such as head
trauma were excluded from the study. The
number of patients diagnosed with idiopathic
BPPV was calculated weekly. A total of 5339
patients were seen by Otorhinolaryngology
in the emergency room during this period. Of
these, 494 had vestibular symptoms and 178
were diagnosed with idiopathic BPPV. Age,
sex, lesion side and the involved semicircular
canal were analyzed. Differences among the
week and seasons of BPPV diagnosis were
evaluated. Spring started from 21st of March
to 20th of June; summer from 21st of June
to 20th of September; autumn from 21st of
September to 20th of December; and winter
from 21st of December to 20th of March.
Climate factors were collected daily from the
Humberto Delgado Airport Meteorological
Station, including daily average atmospheric
temperature (°C), atmospheric pressure (hPa),
humidity (%), cloud amount (cloud covered
area, expressed as 10 fractions of the whole
sky), daylight time (h/day) and solar radiation
(Kwh) in Lisbon Metropolitan area. The weekly
mean value of each factors represented an
arithmetic average of the daily values.
Data analysis
Simple correlation analysis was performed to
evaluate the association between the number
of BPPV patients diagnosed per week and
the weekly mean value of climate factors.
Statistical analysis was performed using IBM
SPSS Statistics version 19 (IBM Corp., Armonk,
NY). Statistical significancy was set at p values
less than 0.05.
Results
Sample characteristics
The age of the 178 patients diagnosed with
idiopathic BPPV ranged from 24 to 91 years,