Now this is an association that had escaped me. Although making no claims to particular expertise in voice work, in my clinical days I was not struck by the raised body mass index of those presenting with dysphonia. Indeed, the old adage of ‘until the fat lady sings’ or the girth of the great tenors almost suggested a need for the professional vocalist to carry a bit of beef.
The Preface presents the frightening statistics of the world's slide into obesity and introduces some suggestions as to how voice problems may result. Basically, the argument is that excess adipose tissue is a meta-inflammatory organ, which produces anatomical and systemic changes in the skeletal musculature, the vibrating cords and the resonating vocal tract. The stated purpose of the book is to ‘review the current literature on the impact of obesity on phonation and to highlight the various means by which excessive weight may jeopardise voice quality and endurance’. As will be seen, ‘may’ is a dominant theme. The challenge for the former objective is the lack of research (to quote, ‘it has scarcely been discussed in the literature’) and the failure to reach any consensus when it is performed. A further aim was to answer the question ‘Does weight loss affect my voice?’
Early chapters then largely provide generic information on voice and its assessment. Fifty pages on the basic sciences of vocal anatomy and physiology contribute nothing novel, but are probably essential in any such textbook. Patient history taking is very well covered in a chapter that also provides a nice history proforma in an appendix, but in which obesity really does not feature. Physical examination then has the expected content, but is illustrated with a marvellous 1964 depiction of head mirror usage in indirect laryngoscopy, all with a mirror warmed over an alcohol flame. Happy but dangerous days, and largely unfamiliar to younger readers.
Now, at page 115, we do start to examine the sparse evidence on ‘Obesity, Body Size and the Voice’, and especially whether blinded observers can predict body size from hearing the spoken word. The answer, as so often the case, does seem to be ‘not proven’. I have read and indeed reviewed much recently on sex hormones and the voice, and of course endocrine disturbance is no surprise in obesity. Alas, despite a very thorough literature search, the closing paragraph of this chapter tells us ‘In summary there are no data to substantiate…’.
The authors are undismayed and determined, and follow this with a chapter on respiratory dysfunction, the basic sciences of physiology and testing. The contribution of the obesity chapter then opens by considering its effect on lung function, and especially its association with asthma and chronic obstructive pulmonary disease (COPD). Alas for asthma, the evidence that obesity then contributes further to recognised voice issues ‘seems likely but has not been proven yet’, while for COPD ‘there are no studies…’.
Never mind, as reflux and obesity do take up the next 150 pages (well over one-third of the book). Laryngopharyngeal reflux (LPR) is blamed for everything from middle-ear effusion to climate change (granted due to bovine methane contributions rather than anything human). Any book on voice problems stresses the role of LPR. Obesity favours LPR. Res ipsa loquitur, surely. Coverage of LPR is certainly comprehensive, with 137 pages and over 600 references on the biochemistry, anatomy, investigation and corrective surgery of reflux. However, the following chapter, on the influence of obesity, comprises only 10 pages, and concludes ‘in summary there is not enough evidence to support an association…’.
The book closes with a chapter on healthy nutrition advice for the professional voice user, which is then followed by ‘Effect of Weight Loss on Voice’. This last was highlighted, remember, in the Preface, as an objective, but it is disappointing to see only eight pages, and to read the opening sentence ‘The effect of weight loss on voice is scarcely discussed in the literature’. As surrogate measures, they instead look at the effect of successful dieting on: vocal tract morphology, reflux, pulmonary function and sex hormones. These are surely factors which affect voice, except we have now learnt that evidence is lacking for all.
This is a book for the specialist in voice disorders, presented by some of the leading lights in the field. It might be argued that it is premature to publish such a book when the evidence is so lacking, but something must drive that. It is important to highlight this shortfall, and it may yet inspire the research community, with its many recommendations, especially as there seems no likelihood of a future lack of subjects. The authors have produced some very convincing arguments to suggest that obesity and voice disorders must logically be associated. Surely they must, and will hopefully be shown as such by the high-level research called for here.
