PUBERTAL MATURATION STATUS

Many studies on growth and development have identified the pubertal maturation of children and adolescents from reproductive endocrine hormonal measures and somatic measures such as skeletal/bone age, age at attainment of adult height and also development of secondary sexual characteristics (Veldre and Jürimäe, 2004). Research on growth and development has been hindered due to the difficulties of assessing pubertal or sexual maturation in epidemiologic research. I also found it difficult to pick an appropriate measure for estimating pubertal maturation, while considering the acceptability of the measure to children and adolescents and to other relevant individuals involved with the assessment.

According to Norris and Richter (2008), the most direct measure of pubertal stage may be reproductive endocrine hormone levels using hormonal assays, however, the many hormones linked with puberty and the practical of challenges of collecting biological samples and the cost of laboratory tests are considerable interferences in using endocrine hormone measures in large community or school-based studies. Somatic measure of pubertal maturation status focuses on indicators such as body weight, height (commonly estimated using age at peak height velocity, that is, age of rapid height increase), skeletal or bone age (using radiographic images), dental development (using radiographic images) and the development of secondary sexual characteristics

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(sexual maturation including: the onset of menstruation (menarche), appearance and advancement of breast, pubic hair, and development of genitalia) (Veldre and Jürimäe, 2004). Skeletal or bone age using radiographic image of the wrist bone is suggested to be one of the most accurate estimate of stage of growth and development status during puberty but is impeded because of X-ray radiation exposure and the relative expense needed, and is thus, not commonly reported (Kozinetz, 1988).

Measures of assessing the development of secondary sexual characteristics (including: menarche, appearance and advancement of breast, pubic hair, and development of genitalia) are the most widely used in epidemiological studies. Though information on menarcheal age is easy to obtain, menarcheal age is prone to reporting bias as menarche could have occurred at the beginning of the age or end of the age, giving a variation in the reported time period between two people with the same age of menarche. It is also prone to recall bias as time may have elapsed between menarche and time of study, thus some individuals may not remember the precise month within the year or even the year (Koo and Rohan, 1997). The most acknowledged standard measure of pubertal development is the sexual maturation stage rating of secondary sexual characteristics (Norris and Richter, 2008). Facchini et al (2008) highlighted that the easiest, accurate, reliable, most common and relatively cost effective direct method of assessing pubertal maturation status is the sexual maturation stage rating. As described in the Literature Review Chapter (Chapter 3), the sexual maturation stage rating was developed by Tanner (1962); it classifies and standardises secondary sex characteristics into five distinct stages, based on pubic hair development in both males and females, breast development in females and genital development in males, ranging from immature to fully mature (Facchini et al., 2008).

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The sexual maturation rating was designed for expert physical examination use of a trained assessor or health professional in order to determine pubertal development in children and adolescents (Peterson et al., 1988). Physical examination of pubertal maturation stages by a trained assessor or health professional is a widely used method (Reinehr and Toschke, 2009; Hoffman et al., 2005; Meininger et al., 2004; He et al., 2002; Cho et al., 2001; Hansen et al., 1990; Vartiainen et al., 1986; Tell, 1985; Orchard

et al., 1980). However, it is considered to be an invasive method which can be

uncomfortable for participants as it requires a considerable amount of physical exposure and it has been opposed by parents, school personnel, and also the children and adolescents in many countries (Wacharasindhu et al., 2002). It may limit the representativeness of a study sample, as some eligible individuals may refuse participation so as to avoid the procedure.

A self-assessment non-invasive conservative indirect method of sexual maturation stage rating has been suggested as an accurate and acceptable alternative method (Petersen et al., 1988). Although prone to recall bias, underestimation and overestimation of pubertal maturation stage, the self-assessment method has been reported to have considerable agreement with the health professional physical assessment (Chan et al., 2008; Leone and Comtois, 2007; Norris and Richter, 2005; Schmitz et al., 2004; Schall et al., 2002; Wacharasindhu et al., 2002; Taylor et al., 2001; Matsudo and Matsudo, 1994; Williams et al., 1988; Brooks-Gunn et al., 1987; Neinstein, 1982; Duke et al., 1980; Morris and Udry, 1980), while some researchers are sceptical about the validity (Azevedo et al., 2009; Desmangles et al., 2006; Wu et al., 2001; Hergenroeder et al., 1999; Schlossberger et al., 1992).

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The self-assessment of pubertal maturation stages involves the child’s or adolescent’s identification of sexual maturation by Tanner stages rating or scale of maturation presented as photographs (Azevedo et al., 2009; Desmangles et al., 2006; Norris and Richter, 2005; Wacharasindhu et al., 2002; Wu et al., 2001; Matsudo and Matsudo, 1994; Schlossberger et al., 1992; Williams et al., 1988; Duke et al., 1980) or line drawings (Chan et al., 2008; Leone and Comtois, 2007; Norris and Richter, 2005; Schmitz et al., 2004; Schall et al., 2002; Taylor et al., 2001; Hergenroeder et al., 1999; Williams et al., 1988; Brooks-Gunn et al., 1987; Neinstein, 1982; Morris and Udry, 1980). In the present study, I considered the five pictorial Tanner stages of breast development and genital development (Tanner, 1962) the most appropriate method for the children and adolescents to assess their own stage of pubertal maturation.