Puberty and Insulin-Dependent Diabetes Mellitus Douglas G. Rogers, M.D.

Introduction

-JL.

uberty is the period of transition from sexual immatur-

ity potential fertility during secondary sexual characteristics develop. Rapid hormonal and metabolic changes occur during puberty. Insulin-dependent diabetes to

which

mellitus mon

(IDDM)

is the most

com-

endocrine/metabolic disorder

of childhood and adolescence. The

profound metabolic derangements caused by IDDM may disrupt the usual progression of hormonal and metabolic

during rapid metabolic changes that occur during puberty may destabilize glycemic control in patients with IDDM and affect the development of certain diabetic complications. This review changes

seen

puberty. Likewise, the

article will examine the effect that puberty has on the course of IDDM and also examine the effect that IDDM may have on puberty.

The Effect of Puberty on Diabetes Management It has been the common experithat levels of glycemia are

ence

Head, Section of Pediatric Endocrinology

Department of Pediatrics The Cleveland Clinic Foundation Cleveland, OH

correspondence to: Douglas G. Rogers, M.D., Department of Pediatrics A-120 , The Cleveland Clinic Foundation, Address

9500 Euclid Ave., Cleveland, 0H 44195-5045 .

(216) 445-8048

168

higher and fluctuate more during puberty in a given individual patient than before puberty. Average blood glucose concentrations can be assessed by measuring glycohemoglobin (HbAi). HbAi is formed when a glucose molecule the N-terminus of the hemoglobin beta chain by ketoamine linkage. When measured, HbAi is reported as a percentage of total hemoglobin. This percent HbAi then serves as an index of the

attaches

to

average blood

glucose

concentra-

tion over the previous two months. Mean HbAi levels are lower in prepubertal children compared to children in puberty, with levels increasing till mid-puberty (stage III) and then falling again during late puberty (stages IV and V) 1,2

(Table 1). It has been assumed by many health-care professionals that the destabilization of glycemic control seen during puberty is due to increased psychosocial pressures which the adolescent with IDDM invariably experiences.3,4 And indeed, an increased level of stress does influence glycemic control in the adolescent patient.’ However, insulin resistance occurs during puberty in both diabetic and nondiabetic adolescents. 5,6 Because of this, the adolescent with IDDM generally requires more insulin on a unit/kg basis than the prepubertal patient, and reluctance on the part of the physician caring for an adolescent with IDDM to dramatically raise insulin dosage during puberty may cause under-treat-

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ment

and increased levels

mia.l,7 Health-care should also be

of glyceprofessionals

aware

that adoles-

girls usually require more inboys of the same pubertal development (Table 2).8 Insulin requirements increase during the early morning hours, causing pre-breakfast hyperglycemia in many patients with IDDM. cent

sulin than adolescent

This is referred to as the &dquo;dawn phenomenon.&dquo; The cause of this increased insulin requirement is controversial. Several studies of the dawn phenomenon have shown that insulin clearance increased during the early morning hours.9-11 It has also been proposed that the nocturnal secretion of growth hormone is directly related to the dawn phenomenon.12,13 Growth hormone secretion increases during puberty, peaking at breast stage II in girls and genital stage IV in boYS.14-16 Thus the dawn phenomenon may become more clinically

apparent during puberty.

Regardless of the mechanisms responsible for the dawn phenomenon, the therapeutic approach would be

to increase the availabilof insulin ity during the dawn period. To accomplish this, many adolescent patients will require changes in insulin dosage regimens that will blunt the dawn phenomenon. This usually entails moving part or all of the pre-evening meal dose of intermediateacting insulin (NPH) to bedtime (10:00 p.m. to 11:00 p.m.). This provides a peak insulin effect in the

Tablet

1~ Viiliès are means

s: ~;~.

p-