LOH–pitfalls of an ambiguous abbreviation

Dear Sir,

We would like to comment on the paper by Nieschlag E, Swerdloff R, Behre HM, Gooren LJ, Kaufman JM, Legros JJ, Lunenfeld B, Morley JE, Schulman C, Wang C, Weidner W, Wu FC. Investigation, treatment and monitoring of late-onset hypogonadism in males. The Aging Male 2005;8:56–58 [1].

In the andrologic literature it has become increasingly common to use the abbreviation LOH for the condition “late-onset hypogonadism”, which denominates the hypogonadism due to decreasing testosterone secretion in the aging male [1].

The history of the term is not clear. It is used in a number of written and oral reviews since 2003. The term is yet unknown in the scientific program of the Second World Congress on the Aging Male (Geneva, Switzerland, February 9–13, 2000), where lack of testosterone in the aging male is designated as ‘PADAM’, an abbreviation for ‘partial androgen deficiency of the aging male’[2]. The Fourth World Congress on the Aging Male (Prague, Czech Republic, February 26–29, 2004) lists presentations using ‘PADAM’[3], ‘age-related hypogonadism’[4] and, for the first time, ‘age-related late-onset hypogonadism’[5].

In 2003, Zitzman & Nieschlag [6] translated the German expression ‘Altershypogonadismus' (hypogonadism of the aging male) in the English summary of a German review for the first time as ‘late-onset hypogonadism’. They proposed to use this term in future and designated it ‘as official description of the disease in the international literature’. Subsequently, the name ‘late onset hypogonadism’ and its abbreviation LOH were used in some of the major publications in the field [7-10].

There are, however, two arguments against this designation. Firstly, the abbreviation LOH is already occupied in the literature by its meaning ‘loss of heterozygosity’, which is a well defined term in both genetics and general medicine. A search for LOH in PubMed presently reveals 7305 hits, of which only 59 refer to the meaning ‘late-onset hypogonadism’. Therefore, if one looks for quotations in the literature, the andrological ‘LOH’ would go under in the flood of genetic LOH.

Secondly, the expression ‘late-onset’ is used in other combinations for diseases that commence in adult age as opposed to postnatal beginning, but it is not used for a manifestation of aging, as is the case in hypogonadism of aging men. In 1997, Nachtigall et al. [11] published a study on men with ‘adult-onset hypogonadotropic hypogonadism’, which described men with symptoms similar to an inborn hypogonadism manifesting in puberty. They concluded that these men had treatable GnRH deficiency similar to that of boys with hypogonadotropic hypogonadism. In our view the term ‘late-onset hypogonadism’, if we should use it at all, would be more fitting to delineate this condition.

Hence, to avert confusion it appears resonable to avoid the term ‘late-onset hypogonadism’ and its abbreviation ‘LOH’ in andrology and to look for another term such as ‘hypogonadism in aging men’ (HAM).

Walter Krause and Rudolf Happle

Department of Dermatology

Philipp University

School of Medicine

D-35033 Marburg

[email protected]