xRead - Olfactory Disorders (September 2023)

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PATEL et al.

TABLE IX-22 (Continued)

Clinical end point

Study

Year LOE Disease

Study design

Study groups 90 patients, 45 primary hypothyroid patients

Conclusions

SS-TDI

Free T3 levels were found to have a more significant relationship with olfactory parameters than thyroid-stimulating hormone or free T4 levels hypothyroid patients exhibited a significantly decreased olfactory sensitivity correctable with treatment Bitter taste positively correlated with T3 with treatment evidence for the link between olfactory loss and obesity Bariatric surgery is effective in reversing obesity and associated OD Gastric bypass surgery does not appear to influence OF gustatory functions improve 6 months after bariatric surgery Subclinical There is strong Both olfactory and

Günbey

2015 3

Cohort

et al 1495

Hypothyroidism

Baskoy

2016 3

Cohort

59 patients, 28 subclinical hypothyroid patients

SS-TDI Taste strips

et al 1497

Hypothyroidism/3 monthsL thyroxine treatmen

Peng

2019 4

Obesity

Review

Review of 19 studies

Multiple measures Meta-analysis of SS-TDI performed on 9 studies

et al 957

Richardson et al 1498

2012 3

Obesity

Cohort

95 patients, 55 gastric bypass surgery 44 orbidly obese patients undergoing bariatric surgery

B-SIT

Holinski et al 976

SS-TDI Taste strips

2015 4

Obesity

Case series

B-SIT = Brief Smell Identification Test; CCCRC = Connecticut Chemosensory Clinical Research Center; DM = diabetes mellitus; HC = healthy control; LOE = level of evidence; MMSE = Mini-Mental Status Examination; OD = olfactory dysfunction; OF = olfactory function; SS-TDI = Sniffin’ Sticks threshold, discrimination, identification combination.

however, vitamin A applied intranasally as an add-on treatment in conjunction with OT, was suggested to be effective for the treatment of postinfectious olfactory loss, but it was an uncontrolled, unblinded, retrospective study, disallowing for any conclusion about true efficacy in a nondeficient patient population. 457 Iron deficiency is also associated with olfactory deficits 954 that improve with iron replacement. 1511 Vita min B12 deficiency is also a cause of reversible OD, as well as mild cognitive impairment. 1512 Consequently, it is possible that the correction of vitamin B12 deficiency

improves olfaction via the reversal of the mild deficit in neurocognitive processing. 1289,593 Vitamin B1 (thiamin) replacement has been found to be effective in the management of smell loss caused by PD. Håglin et al 1513 Reported that thiamine and folic acid deficiency in the diet, especially 2 to 8 years before the diagnosis of PD, led to OD. It was suggested by Heil mann at al 1514 that vitamin B1 deficiency causes odor loss and that long-term replacement can be an effective treatment. In this study, vitamin B treatment was com pared with local and systemic corticosteroid treatments.