MATERIALS AND METHODS

Source of Data: The data presented were obtained from the radioimmunoassay (RIA) laboratory of the Institute of Radiotherapy and Nuclear Medicine (IRNUM) Peshawar. Patients from all parts of NWFP, adjacent tribal areas and Afghanistan are referred to the laboratory. The laboratory keeps the record of the patients.

The record of 25237 thyroid patients, visited the RIA laboratory of IRNUM during the years 1984-1990 (except 1987), 1995 and 1996 for thyroid and thyroid stimulating hormones test was available in the laboratory. This record was obtained from the laboratory for compilation and statistical analysis.

Classification of the Data: The refereed patients were of all age groups and different sex. Out of 25237 patients, age and sex were known of 24522 and 25087 patients, respectively. The data was classified on the basis of age into infants (0-1 years), children (>1-13 years), adult (>13-40 years), old age (>40 years) and into males and females group on the basis of sex. On the basis of date of referral, the data was divided into winter (Nov.-Jan.), spring (Feb.-April), summer (May-Jul.) and autumn (Aug.-Oct.).

Statistical Analysis: The data was statistically analyzed with correlation analysis and general linear model procedures by using available SAS statistics package (SAS, 1990). The percent distribution of thyroid patients based on age groups, sex, seasons and years was compiled.

RESULTS

All the thyroid patients who were referred to the RIA laboratory during the years of the study as a whole and during each year and their percent distribution among the various age groups are presented in Table 1. The over all distribution of thyroid patients in different age groups is presented in Table 2. The distribution of thyroid patients among the different age groups was almost constant throughout the study period (Tables 1 and 2). The thyroid patients in the infant group ranged from 0.6 to 1.6% in the different years with an average value of 0.8%. Similarly, the patient in the children group ranged from 7.0 to 12.4 % in different years of the study with an average value of 8.4%. The thyroid patients in the adult group ranged from 59.0 to 66.1% during the study years with an average value of 64.0%. The thyroid patients in the old age group ranged from 25.6 to 31.4% in the different years with an average value of 27.0%.

Table 1:	Years wise distribution of thyroid patients in different age groups
The bold figures in row number 1,2,7,12,17,22,27,32 and 37 in column 3 indicate the total number of thyroid patients in the respective years. The bold figures in the same rows in column 4 indicate percent total of each year. The remaining figures indicate the number and percent of the particular years.

Table 2:	Over all distribution of thyroid patients in different age groups

Table 3:	Yearwise distribution of thyroid patients in different sex

Table 4:	Over all distribution of thyroid patients in different sex

The yearwise and average distribution of thyroid patients in males and females are shown in Tables 3 and 4. The yearwise distribution of thyroid patients between males and females ranges from 25 to 37% males and 63 to 75% females in different years, with an average value 27 and 73% for male and females, respectively. The yearwise and the average referral of thyroid patients to the RIA laboratory in different seasons are given in Tables 5 and 6. The yearwise referral in winter ranged from 22.1 to 41.4% with an average value of 28.6%. Similarly, the yearwise referral in spring ranged from 23.0 to 40.6 % with an average value of 24.6%. The yearwise referral in summer ranged from 15.6 to 39.7% with an average value of 30.9%. The referral in autumn ranged from 3.1 to 57.9% with an average value of 15.9%.

DISCUSSION

The data indicated that the referral of thyroid patients to the RIA laboratory had been increased over the years from 1984 to 1996. The only exception was that the thyroid patients in 1985 and 1989 were less than thyroid patients in the preceding year i.e., 1984 and 1988, respectively. It was also noted that there was some missing data for the years 1985 and 1989 in the record of laboratory and perhaps the decrease in the referral in those years was due to that missing data. The reason for the general increase in the referral of thyroid patients over the years might be that people had become more educated over the years in terms of health care and they had started consulting their physicians, whenever they had health problems. Also the physicians had become more dependent on laboratory tests over the years. This seemed a possibility that with the passage of time, the sensitivity of the tests performed by the RIA laboratory has been improved and has gained more confidence of doctors who were referring their patients for thyroid hormones test to the laboratory. An additional reason for the increased referral may be the increased frequencies of thyroid problems due to the use of iodized salt or other unknown reasons. More intake of iodine in the form of iodized salt may causes thyroid problems particularly thyrotoxicosis (Kelly, 1960; Connolly 1971; 1973; Stewart et al., 1971; Vidor et al., 1973).

Increased population may also be a reason for the increase. The percent referral in 1996 (28.4%) was 6 times more than the percent referral in 1986 (4.5%). The increase referral of thyroid patients over the years is really a matter of concern for the health professionals. They are required to find the causes of the increase and they would have to develop a strategy for control of this situation.

The distribution of thyroid patients among the different age groups (Table 2) was almost constant throughout the study period. The majority (64%) of patients were in the adult age group followed by old age (27%), children (8.4%) and infants (0.8%). The difference in frequencies of thyroid related problems in different age groups was significant at 0.05 % level. Miller and Block (1970) have reported increased frequencies of thyroid problems with age. They have suggested that gradual increase in autonomous tissues with age, making individuals more susceptible to thyroid problems. Lavard et al. (1994) also reported that thyroid problems were less prevalent in infants and children and were increased with age. However, ICCIDD (1997) reported higher frequencies of thyroid problems in old age people above 40 years. This difference may be because of their study design.

The distribution of thyroid patients among males and females was about 1:3. The data (Table 4) indicated a high frequency of thyroid problems in females. The frequency of thyroid problems between males (27 %) and females (73 %) was significantly different at p<0.05. The higher frequency of thyroid problems in females patients may be attributed to stress related to multiple pregnancies and lactation. Due to the particular family set up in this country, females are more exposed to nutritional deficiencies that can cause health problems including thyroid disorders. Stephen (1992) reported that Asian women had more economic and domestic responsibilities than men. Poor and illiterate women and their children were more prone to nutritional problems such as goiter, anemia and other disorders. ICCIDD (1997) also reported greater frequency of thyroid problems in females than males.

Table 5:	Yearwise distribution of thyroid patients in different seasons

Table 6:	Over all distribution of thyroid patients in different season

The various distributions of thyroid patients in different seasons, reported in this study, might be just a chance as there is no indication in literature that seasons have any effect on the frequencies of thyroid problems.

In conclusion, thyroid problems have been increased over the years and majority of the thyroid problems occur in adult age and females. The physicians are required to find ways and means to control the problems.

ACKNOWLEDGMENTS

We are thankful to Dr. Sher Muhammad Khan, Director IRNUM, Peshawar for permission to compile the data.