Table 1.

Effect of lifestyle factors on thyroid-stimulating hormone, thyroid hormone and thyroglobulin levels in healthy individuals.

Factor			Effect on Hormone Levels	Number of Participants	Reference
Smoking			↓TSH, ↑fT4, ↑fT3	5766	[16]
			↓TSH, fT4, fT3	4585	[146]
			↓TSH, ↑fT4	895	[21]
			↓TSH, fT4	4357	[28]
			↓TSH	15,181	[27]
			↓TSH, fT4	3404	[251]
			↓TSH	5639	[252]
			↓TSH	4427	[253]
			↓TSH, ↓tT4, ↑Tg	1409	[208]
			↓TSH, ↓tT4, fT4, tT3, ↑fT3, ↑Tg	1540	[254]
			↓TSH	1581	[255]
			TSH, fT4, ↑fT3	931	[256]
			↓TSH, fT4	3399	[26]
			↓TSH, ↓tT4, ↓tT3	237	[257]
			↓TSH, fT4	1853	[64]
			↓TSH, ↑fT4, ↑fT3	7799	[22]
			↓TSH	30,834	[25]
			↓TSH, ↑fT4, ↑fT3	6085	[258]
			↓TSH, T4	15,592	[24]
			↓TSH, ↑T4	4462	[259]
			↓TSH, T4, fT4, T3, fT3	1154	[260]
			↓TSH, T3	4100	[261]
			TSH, T4, ↑T3	50	[262]
			↓TSH, T4, T3, ↑Tg	219	[263]
			↓TSH, ↑T4, T3	181	[264]
			TSH, ↓T4, ↓T3	200	[265]
			↓TSH, T4, ↑T3, ↓rT3, ↑Tg	441	[266]
Alcohol consumption			↑TSH, ↓fT3	5766	[16]
			TSH, ↓fT4	549 (men)	[40]
			TSH, ↓fT4, ↓fT3	67	[39]
			TSH, T4, T3	100	[38]
			TSH, T4, ↑T3	30
			TSH, fT4, ↓T4, fT3, T3	55	[37]
			↑fT4	21	[43]
			TSH, T4, fT4, ↓T3, ↓fT3	70	[36]
			↑TSH, T4, fT4, ↓fT3, ↓T3	80	[41]
			TSH, T4, T3, ↑Tg	111	[44]
			TSH, fT4, ↓tT4, ↓tT3	38	[42]
Increased body mass index			TSH, ↓fT4	90	[267]
			↑TSH (BMI higher than 25.3 kg/m2)	11,224	[268]
			↓TSH (BMI lower than 25.3 kg/m2)
			↑TSH	75	[269]
			↑TSH	2789	[15]
			TSH, fT4, fT3	34	[270]
			↑TSH, ↓fT4, ↑fT3	77,991	[9]
			TSH	88	[271]
			↓fT4, ↑fT3, ↑fT3/ fT4	16,975	[65]
			TSH, fT4, ↓fT3	36,655 (all subjects)	[272]
			↓fT4	18,746 (men)
			↑TSH	80	[273]
			TSH, ↓fT4	7693	[274]
			TSH, ↓fT4	1100	[275]
			↑TSH	140	[276]
			TSH, fT4, ↑fT3	940	[277]
			↑TSH, ↓fT4, fT3	26,719	[56]
			TSH, fT4, fT3	1275	[278]
			TSH	162	[279]
			↑TSH, ↓fT4	9402	[8]
			↑TSH	800	[280]
			TSH	1097	[281]
			↑TSH, fT4, tT4, fT3, ↑tT3, ↑Tg	746 (men)	[208]
			↑TSH	1044 (men)	[282]
			TSH, ↓fT4, ↑fT3, ↑tT3, ↑fT3/ fT4	2315	[60]
			TSH, ↓fT4	6241 (all subjects)	[283]
			↓TSH	2837 (women)
			TSH, fT4, ↑tT4, fT3, ↑tT3	736	[67]
			↑TSH	417	[284]
			↑TSH	5918	[285]
			↑TSH, fT4, fT3	60	[286]
			fT4, ↑fT3	865	[287]
			↑TSH, fT4, ↑fT3	3114	[288]
			↑TSH, fT4	778	[289]
			↑TSH	1084	[290]
			↑TSH	15,020	[291]
			↑TSH, fT4	581	[292]
			↑TSH, fT4, ↑fT3	520	[59]
			TSH, fT4, ↑T3, ↑T3/fT4	275	[293]
			↑TSH, fT4, tT3	27,097	[53]
			TSH, ↓fT4	44,196	[294]
			TSH, ↓fT4	1853	[64]
			↑TSH, fT4, ↑fT3	152	[242]
			TSH, ↓fT4	1572	[295]
			↑TSH, fT4, fT3	265	[296]
			↑TSH, fT4	86	[297]
			TSH, fT4, ↑fT3, ↑fT3/ fT4	201	[57]
			↑TSH	1725	[23]
			↑TSH, fT4, fT3	87	[298]
			↑TSH, ↓fT4, fT3	4082	[55]
Diet	Soy food or soy isoflavones		↑TSH, fT4, fT3	Meta-analysis	[14]
			↑TSH, ↓fT4, fT3, ↑rT3	400	[96]
			↑TSH, ↓fT4, fT3	200	[95]
			TSH, fT4, fT3	47	[93]
			TSH, fT4	505	[299]
			TSH, fT4, ↓fT3	43	[100]
			TSH, fT4	403	[94]
			TSH, fT4, fT3	93	[300]
			TSH, fT4	63	[301]
			TSH, fT4, fT3	389	[92]
			TSH, T4	Meta-analysis	[302]
			TSH	77	[303]
			TSH, fT4, tT4, fT3, tT3, Tg	147	[91]
			TSH, fT4, tT4, fT3, tT3	35	[90]
			TSH, T4, T3, fT4	25	[143]
			TSH	89	[304]
			TSH, T4, T3	38	[89]
			TSH, ↓fT4, fT3	32	[98]
			↑TSH, ↑T4, ↑T3	73	[97]
			TSH	76	[305]
			TSH, fT4, ↓fT3, T4, T3	14	[306]
			TSH, fT4, tT4, fT3, tT3	18	[99]
	Brassica vegetables	Sulforaphane (natural product present in cruciferous vegetables like broccoli)	TSH, T4, Tg	45	[109]
		Roots of cruciferous plant Lepidium peruvianum Chacon	TSH, T4, T3	20	[108]
		Brussels sprouts	TSH, tT4, fT4, tT3	10	[107]
	Other food	Seaweed	↑TSH, fT3, fT4	19	[144]
		Seaweed	↑TSH (returned to normal after several days), fT4	9	[145]
		Seaweed	↑TSH (returned to normal after several days), ↓fT4, ↓fT3 (returned to normal after several days)	13	[141]
		Seaweed	↑TSH, T4, T3, fT4	25	[143]
		Kelp	↑TSH, fT4, ↓fT3	36	[142]
		Kelp, vegans vs. omnivores	↑TSH	101	[307]
		Full-fat cheese, cottage cheese, hard cheese	↓fT4	4585	[146]
		Pasta and rice	↑fT4
		Whole-grain bread	↓fT4
		White bread	↑fT4
		White fish, blue fish, dried fish, seafood, squid	↑fT4, ↑fT3
		Fruit juices, cedevita, nonalcoholic drinks	↓TSH, ↑fT4
		Pork, beef, eggs	↓fT4
		Bacon, sausages	↑fT4, ↑fT3
		Butter, animal fat	↓fT4
		Canned vegetables, mushrooms	↓fT4, ↓fT3
		Powder soups, vegetable juices	↑fT4
		Venison, fish derivates	↓TSH
		Non-home-made meal	↑T4	100	[147]
		Whole grains, green tea	↓T3
		Pasta	↑fT4
	Olive oil	Mediterranean diet	TSH, ↓fT4, ↓fT3	324	[120]
		Olive oil	TSH, ↓fT4, ↓fT3
		Vegetables cooked with olive oil	↑T3	100	[147]
	Food associated with the development of endemic goiter	Cassava	↓T4, ↓T3	20	[308]
	Beverages	Coffee	TSH, ↑fT4	9408	[164]
		Coffee	TSH, T3	Not reported	[163]
	Micronutrients	↑ Vitamin D	TSH, ↑fT4, fT3	123	[309]
		↑ Vitamin D	TSH, ↓T4, ↓T3	300	[184]
		↓ Vitamin D	TSH, fT4	2006	[310]
		↓ Vitamin D	↑TSH	294	[182]
		↑ Vitamin D	↓TSH	1424	[183]
		↑ Vitamin D	↓TSH	2582	[175]
		↑Selenium	TSH, ↓fT4, fT3	69	[207]
			TSH, ↑fT4	184 (women)	[229]
			TSH, T4, fT4, T3, rT3	387	[311]
			↓TSH, ↓fT4, fT3	361	[206]
			TSH, fT4, fT3, Tg	1383	[208]
			TSH, ↓fT4, ↓fT3	1144	[205]
TSH, ↑fT4			140	[312]
TSH, tT4, ↑T3,			28	[313]
TSH, fT4, fT3, Tg			88	[314]
TSH, T4, T3			42	[315]
TSH, ↓fT4, fT3			52	[316]
TSH, ↓fT4, tT4, fT3, tT3, ↑fT3/fT4			368	[204]
↑TSH, ↓T3			12	[317]
TSH, fT4, fT3, fT3/fT4			44	[219]
↓T4, Tg			52	[203]
TSH, ↓T4, T3, ↑T3/T4			109	[202]
TSH, ↓T4, ↓fT4, T3, ↓rT3			52	[201]
↑Zinc		TSH, fT4, fT3	98	[217]
		TSH, ↓tT4, ↓fT4, tT3, fT3	746 (men)	[208]
		TSH, fT4, ↑fT3	64	[220]
		TSH	219	[318]
		↓tT4, tT3	178	[218]
		TSH, fT4, ↑fT3, ↑fT3/fT4	44	[219]
		TSH, tT4, fT4, tT3	109	[202]
Iron deficiency		TSH, ↓fT4, ↓fT3	3846	[228]
Iron deficiency anemia		TSH, ↓tT4, fT4, ↓tT3, fT3	128	[227]
Anemia		TSH, fT4, tT4, ↑fT3	50	[226]
Iron supplements		TSH, fT4, ↑tT4, ↑tT3, ↓rT3	94	[319]
Anemia		↓fT4, ↓fT3	20	[320]
↑Copper		TSH, ↑fT4	417	[229]
		TSH, ↑fT4, ↑tT4, fT3, tT3, Tg	746 (men)	[208]
		TSH, fT4, ↑tT4, fT3, ↑tT3, Tg	663 (women)
Iodine excess		↑TSH	Meta-analysis	[240]
		↑TSH	78,470	[241]
		↑TSH, fT4, ↓fT3	854	[239]
		↑TSH, ↓fT4, ↓fT3	236	[321]
		↑TSH, ↓fT4, ↓fT3	256	[238]
		↑TSH, ↓fT4, ↑Tg	10	[237]
		↓T4, T3	30	[235]
		↑TSH, ↓T4, ↓T3	32	[236]
Exercise			TSH, fT4	2470	[250]
			↓TSH, ↑T4, ↑T3	36	[248]
			TSH, ↑fT4, ↑fT3	9	[247]
			↑TSH, ↑fT4, ↑T4, ↓fT3, ↓T3	60	[249]
			TSH, fT4, T4, fT3, T3	26	[246]
			↑fT4, ↓fT3, ↓T3, ↑rT3	27	[322]
			TSH	6	[323]
			fT4, T4, fT3, T3, rT3	46	[324]
			↑TSH, ↑fT4	14	[325]
			T4, ↑T3, ↑rT3	12	[326]
			↑T4, ↓T3, ↑rT3	4	[327]
			↑TSH	8	[328]

Studies involving pregnant women, infants, children and individuals with a history of thyroid diseases were not included in this table. rT3, reverse triiodothyronine; T3, triiodothyronine; T4, thyroxine; tT3, total T3; tT4, total T4; Tg, thyroglobulin; TSH, thyroid-stimulating hormone.