Seasonal variation in the diagnosis of Graves' disease.
OBJECTIVE
Heat intolerance is a well known symptom of Graves' disease. Therefore, it is possible that increased ambient temperature could influence the recognition of Graves' disease by unmasking or enhancing the symptom of heat intolerance. Our aim was to determine if there is a seasonal variation in the diagnosis of Graves' disease.


METHODS
A retrospective study.


METHODS
A county hospital and clinic.


METHODS
Two hundred and seven patients with Graves' disease diagnosed from 1985 to 1992.


RESULTS
A high correlation was found between the temperature and the number of cases of Graves' disease diagnosed. A larger proportion of patients (68%) was diagnosed during the warmer half of the year, May-October, than during the cooler half. The peak incidence of the diagnosis occurred in May, when 17.4% of the patients were diagnosed. Although the peak average monthly temperature occurs in July, the month of May corresponds to the time of the year when the temperature is making its largest positive change in the month-to-month variation.


CONCLUSIONS
Seasonal variations in the temperature can affect the incidence of the diagnosis of Graves' disease. The diagnosis is more common during the months of higher temperature.
Westphal
S A
SA
Department of Medicine, Maricopa Medical Center, Phoenix, Arizona 85008.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D006358:Hot Temperature; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012621:Seasons; D013961:Thyroid Gland / Q000503:physiopathology; D013963:Thyroid Hormones / Q000097:blood; D014481:United States
D013963:Thyroid Hormones