xRead - Olfactory Disorders (September 2023)

20426984, 2022, 4, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22929, Wiley Online Library on [04/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

483

PATEL et al.

TABLE VII.17 (Continued) Author Year

Design LOE Study groups

Olfactory indicator Smoking measure Conclusions

Odor identification Current, former, never

Pooled analysis showed that smoking was associated with a 59% increased odds of OD Significantly increased odds of OD was not

1

7 studies included 11,771 participants (highlighted in orange above)

Ajmani

2017

Meta

et al 982

analysis of obser vational studies between 1970and 2015

seen in former smokers than never-smokers

BAST-24 = Barcelona Smell Test-24; B-SIT = Brief Smell Identification Test; CABG = coronary artery bypass grafting; CCCRC = Connecticut Chemosensory Clinical Research Center; CRS = chronic rhinosinusitis; CT = computed tomography; ECRS = eosinophilic chronic rhinosinusitis; ESS = endoscopic sinus surgery; LOE = level of evidence; NECRS = noneosinophilic chronic rhinosinusitis; NHANES = National Health and Nutrition Examination Survey; NP = nasal polyp; OD = olfactory function; OF = olfactory function; PD = Parkinson disease; PEA = phenylethyl alcohol; PST = Pocket Smell Test; RCT = randomized controlled trial; SDOIT = San Diego Odor Identification Test; SIT = Smell Identification Test; SS-ID = Sniffin’ Sticks identification only; SS-T = Sniffin’ Sticks threshold only; SS-TDI = Sniffin’ Sticks threshold, discrimination, identification combination; T&T = Toyoda and Takagi; UPSIT R = University of Pennsylvania Smell Identification Test; VAS = visual analog scale.

Extremely low body weight is not associated with increased OD risk Aggregate grade of evidence : B (Level 3: one study; Level 3b: 10 studies; Level 4: six studies). Extremely high body weight increases OD risk. Weight loss might reverse obestity-related OD. Aggregate grade of evidence : B (Level 2: one study; Level 3b: 14 studies; Level 4: 12 studies; Level 5: one study). O Related to smoking Chronic cigarette smoking may contribute to OD. Litera ture evaluating chronic smoking on OF includes a meta analysis, concluding that current (but not necessarily for mer) smoking was associated with 59% greater OD risk. 982 Additional studies are reviewed below and in Table VII.17. All interventional studies with measured olfaction show OF improvement with smoking cessation, nasal irrigation, and NP surgery for smokers with postsurgery smoking cessation. 983–986 One longitudinal study showed reversal of smoking mediated OD, although OD may persist years after smoking cessation. The other longitudinal study reported current smoking to be associated with greater OF decline. 987,988 One nationally representative cross-sectional study showed that ever- versus never-smokers had significantly lower OD risk and the other nationally representative cross-sectional study did not show a significant relation ship between smoking and OD. 528,989 Nine population-based studies showed greater OD risk among smokers, and two did not. 114,133,354,990–997 Of community-based studies, six studies showed greater OD risk among smokers, with one demonstrating dose-response relationships. Two only studies included

patients with AN. One systematic review concluded that there might be alterations of OF in patients with AN. 871 The current review summarizes all studies that measured OF in patients with extremely low BMI. Most studies utilized the SS threshold, discrimination, identification combination (SS-TDI) test. 941–952 While older studies showed significant heterogeneity of reported results and conclusions, 941,942,944–947,953–956 three recently published studies 943,951,952 provided further evidence that there might exist no relevant differences in OF between patients with AN and controls. Furthermore, those studies that concluded significant differences between patients with AN and controls only showed marginal differences. 941,942,945–950,953,955,956 The literature evaluating the impact of extremely high BMI on OF included one systematic review that concluded solid evidence for a negative correlation between indi vidual body weight and OF. 957 The current review sum marizes all studies that measured OF in patients with extremely high BMI. Most studies utilized the SS-TDI test. 949,951,958–961 Eight studies showed greater OD risk among obese patients. 949,951,958,962–966 Five studies showed no relevant association between extremely high BMI and OD. 961,967–970 One study showed an age-dependent association between BMI and OF, 971 and the remaining two studies reported better OF in morbid obesity. 960,972 One cross-sectional study revealed a positive correla tion between correctly identified odors and BMI, 129 while the longitudinal study revealed no relevant association between BMI and OF. 81 Two cross-sectional studies reported a higher OD risk for morbidly obese patients. 973,974 Five interventional stud ies showed that OF improved significantly after bariatric surgery. 975–980 Two studies showed no effect of bariatric surgery on OF. 963,981