J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://www.jocmr.org

Original Article

Volume 14, Number 3, March 2022, pages 126-135

Population Status of Iodine and Its Potential Effects on Thyroid Function and Autoimmunity in Southwestern Colombia

Figure 2. mUIC according to negative or positive TRAb, anti-Tg and anti-TPO. *mUIC (µg/L) in TRAb negative or positive subjects was 152.8 (IQR: 219.7) and 178.7 (IQR: 287.4), respectively. In anti-Tg negative or positive subjects mUIC (µg/L) was 150.5 (IQR: 219) and 301 (IQR: 289.2), respectively. In anti-TPO negative or positive subjects mUIC (µg/L) was 152 (IQR: 221.4) and 176 (IQR: 236.8), respectively. mUIC: median urinary iodine concentration; TRAb: anti-TSH receptor; anti-Tg: anti-thyroglobulin; anti-TPO: anti-thyroid peroxidase.

**Table 1.** Sociodemographic and Anthropomorphic Characteristics, and Family History of Thyroid Disorders
Variables	Frequency	Percentage (%)
^aFirst-degree family history (self-reported) of goiter, hypothyroidism, hyperthyroidism, and thyroid cancer. BMI: body mass index; SES: socioeconomic status.
Gender
Female	336	81.6
Male	76	18.4
Age in years
< 40	189	45.9
40 - 59	171	41.5
≥ 60	52	12.6
Ethnicity
Mestizo	397	96.4
Indigenous	87	1.9
Afro descendent	7	1.7
Origin
Rural	146	35.4
Urban	266	64.6
SES
Low	314	76.2
Medium	62	15.1
High	36	8.7
BMI (kg/m²)
Low weight	6	1.5
Normal	136	33
Overweight	173	42
Obesity I	75	18.2
Obesity II	17	4.1
Obesity III	5	1.2
Family history of thyroid disorders (self-reported)^a
Yes	154	37.4
No	258	62.6

Table 1. Sociodemographic and Anthropomorphic Characteristics, and Family History of Thyroid Disorders

Variables

Frequency

Percentage (%)

^aFirst-degree family history (self-reported) of goiter, hypothyroidism, hyperthyroidism, and thyroid cancer. BMI: body mass index; SES: socioeconomic status.

Gender

Female

336

81.6

Male

18.4

Age in years

< 40

189

45.9

40 - 59

171

41.5

≥ 60

12.6

Ethnicity

Mestizo

397

96.4

Indigenous

1.9

Afro descendent

1.7

Origin

Rural

146

35.4

Urban

266

64.6

SES

Low

314

76.2

Medium

15.1

High

8.7

BMI (kg/m²)

Low weight

1.5

Normal

136

Overweight

173

Obesity I

18.2

Obesity II

4.1

Obesity III

1.2

Family history of thyroid disorders (self-reported)^a

Yes

154

37.4

258

62.6

**Table 2.** Distribution of mUIC According to Gender, SES and Origin
Variables	mUIC	N	P-value
mUIC: median urinary iodine concentration; SES: socioeconomic status.
Gender
Female	85 (25.3%)	150 (44.6%)	10 (3%)	91 (27.1%)	336	0.065
Male	15 (19.7%)	26 (34.2%)	3 (3.9%)	32 (42.1%)	76
Total					412
SES
High	5 (13.9%)	6 (16.7%)	4 (11.1%)	21 (58.3%)	36	≤ 0.001
Middle	9 (14.8%)	23 (37.7%)	2 (3.3%)	27 (44.3%)	61
Low	86 (27.3%)	147 (46.7%)	7 (2.22%)	75 (23.8%)	315
Total					412
Origin
Rural	34 (23.3%)	83 (56.8%)	3 (2.1%)	26 (17.8%)	146	≤ 0.001
Urban	66 (24.8%)	93 (35%)	10 (3.8%)	97 (36.5%)	266
Total					412

Table 2. Distribution of mUIC According to Gender, SES and Origin

Variables

mUIC

P-value

Low intake

Adequate

More than adequate

Excessive

mUIC: median urinary iodine concentration; SES: socioeconomic status.

Gender

Female

85 (25.3%)

150 (44.6%)

10 (3%)

91 (27.1%)

336

0.065

Male

15 (19.7%)

26 (34.2%)

3 (3.9%)

32 (42.1%)

Total

412

SES

High

5 (13.9%)

6 (16.7%)

4 (11.1%)

21 (58.3%)

≤ 0.001

Middle

9 (14.8%)

23 (37.7%)

2 (3.3%)

27 (44.3%)

Low

86 (27.3%)

147 (46.7%)

7 (2.22%)

75 (23.8%)

315

Total

412

Origin

Rural

34 (23.3%)

83 (56.8%)

3 (2.1%)

26 (17.8%)

146

≤ 0.001

Urban

66 (24.8%)

93 (35%)

10 (3.8%)

97 (36.5%)

266

Total

412

**Table 3.** Comparison of the Clinical Characteristics of Adults With Various mUIC
Characteristics	Deficiency (< 100 µg/L)	Adequate (100 - 199 µg/L)	More than adequate (200 - 299 µg/L)	Excessive (≥ 300 µ/L)	P-value^a
^aANOVA, HSD Tukey. P < 0.05: between the group with excessive vs. deficient mUIC; between the groups with excessive vs. adequate mUIC; between the groups with excessive vs. deficient mUIC; **between the groups with excessive vs. adequate mUIC. Anti-Tg: anti-thyroglobulin; anti-TPO: anti-thyroid peroxidase; BMI: body mass index; IQR: interquartile range; mUIC: median urinary iodine concentration; SD: standard deviation; TRAb: anti-TSH receptor; TSH: thyrotropin.
Number of participants	100	176	13	123	-
mUIC (IQR)	70.1 (58.6 - 86.1)	143.9 (122.6 - 168)	230.5 (209.6 - 289.1)	408 (353.8 - 518)	≤ 0.001*
Age in years (median (SD))	41.3 (12.7)	40.7 (13.14)	48.2 (17.4)	45.5 (17.1)	0.013**
BMI (mean (SD))	27.2 (4.2)	26.7 (5.0)	26.3 (2.8)	26.4 (3.6)	0.58
TSH (median (IQR))	2.1 (1.48 - 3.19)	2.4 (1.63 - 3.47)	3.12 (1.18 - 5.33)	2.82 (1.13 - 4.74)	0.034***
TRAb (median (IQR))	0.10 (0.08 - 0.13)	0.10 (0.10 - 0.10)	0.10 (0.07 - 0.10)	0.10 (0.09 - 0.10)	0.791
Anti-Tg (median (IQR))	20 (19.2 - 29)	20 (20 - 24.75)	20 (20 - 33.5)	21 (20 - 34)	0.008****
Anti-TPO (median (IQR))	10 (9.8 - 20.12)	10.8 (10 - 23.25)	26 (10 - 49.5)	16 (10 - 31)	0.58

Table 3. Comparison of the Clinical Characteristics of Adults With Various mUIC

Characteristics

Deficiency (< 100 µg/L)

Adequate (100 - 199 µg/L)

More than adequate (200 - 299 µg/L)

Excessive (≥ 300 µ/L)

P-value^a

^aANOVA, HSD Tukey. P < 0.05: *between the group with excessive vs. deficient mUIC; **between the groups with excessive vs. adequate mUIC; ***between the groups with excessive vs. deficient mUIC; ****between the groups with excessive vs. adequate mUIC. Anti-Tg: anti-thyroglobulin; anti-TPO: anti-thyroid peroxidase; BMI: body mass index; IQR: interquartile range; mUIC: median urinary iodine concentration; SD: standard deviation; TRAb: anti-TSH receptor; TSH: thyrotropin.

Number of participants

100

176

123

mUIC (IQR)

70.1 (58.6 - 86.1)

143.9 (122.6 - 168)

230.5 (209.6 - 289.1)

408 (353.8 - 518)

≤ 0.001*

Age in years (median (SD))

41.3 (12.7)

40.7 (13.14)

48.2 (17.4)

45.5 (17.1)

0.013**

BMI (mean (SD))

27.2 (4.2)

26.7 (5.0)

26.3 (2.8)

26.4 (3.6)

0.58

TSH (median (IQR))

2.1 (1.48 - 3.19)

2.4 (1.63 - 3.47)

3.12 (1.18 - 5.33)

2.82 (1.13 - 4.74)

0.034***

TRAb (median (IQR))

0.10 (0.08 - 0.13)

0.10 (0.10 - 0.10)

0.10 (0.07 - 0.10)

0.10 (0.09 - 0.10)

0.791

Anti-Tg (median (IQR))

20 (19.2 - 29)

20 (20 - 24.75)

20 (20 - 33.5)

21 (20 - 34)

0.008****

Anti-TPO (median (IQR))

10 (9.8 - 20.12)

10.8 (10 - 23.25)

26 (10 - 49.5)

16 (10 - 31)

0.58

**Table 4.** Adjusted PR for Hypothyroidism^a
Variables	Category	Adjusted PR	95% CI	P-value
^aHypothyroidism was tentatively defined as TSH > 4.0 mIU/L. Confounding variables for adjustment included: age, gender, SES and levels of mUIC. CI: confidence interval; mUIC: median urinary iodine concentration; PR: prevalence ratio; SES: socioeconomic status; TSH: thyrotropin.
Age (years)	≥ 60 vs. < 40	2.45	1.59 - 3.78	≤ 0.001
Gender	Female vs. male	1.52	1.10 - 2.09	0.01
SES	Low vs. high	0.53	0.36 - 0.78	≤ 0.001
mUIC	Excessive vs. adequate	2.73	1.47 - 5.08	≤ 0.001

Table 4. Adjusted PR for Hypothyroidism^a

Variables

Parameter	Variables	PR	95% CI	P-value
^aConfounding variables for adjustment included: gender, elevated TSH, origin, and SES. CI: confidence interval; mUIC: median urinary iodine concentration; PR: prevalence ratio; SES: socioeconomic status; TSH: thyrotropin.
mUIC ≥ 300 µg/L	Gender (female vs. male)	1.916	1.089 - 3.370	0.011
	Elevated TSH (vs. normal)	1.726	1.015 - 2.935	0.010
	Origin (rural vs. urban)	3.11	1.88 - 5.34	0.01
Goiter	SES (middle vs. high)	0.60	0.39 - 0.91	0.02