Barbara A. Cromer

Low levels of 25-hydroxy vitamin D are associated with elevated parathyroid hormone in healthy adolescent females

This study aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH)D)] and parathyroid hormone (PTH) levels in adolescent females residing in a northern climate. Concern regarding vitamin D status in this population is due to limited sunlight exposure in northern latitudes, decreased outdoor recreational activities, as well as decreased conversion in black girls from increased skin pigmentation. In this cross-sectional analysis, serum samples were assayed for 25(OH)D using competitive protein binding (CPB) assay and PTH with immuno-radiometric (RIA) procedures. Four hundred postmenarcheal females (12–18 years) residing in northeastern Ohio were recruited. Subjects were excluded if they had a history of bone, kidney, or liver disease, or used medications that affect bone. The primary goal was to determine serum 25(OH)D concentrations in relation to circulating PTH levels in a population of adolescent girls. The Spearman correlation test was used to compare PTH and 25(OH)D. Fit multiple split models were run to determine change in slope of the regression line when 25(OH)D and PTH were plotted. Analysis of variance was determined using modeled means with differences by race and season in the final model. Unadjusted mean serum 25(OH)D and PTH levels were 55.0±30.4xa0nmol/l and 39.4±20.6xa0ng/l, respectively. Blacks had lower 25(OH)D and higher PTH compared with non-blacks (P<0.0001), especially during the winter months. Decreasing 25(OH)D was inversely correlated with PTH (r=−0.314) (P<0.0001), and at concentrations of 25(OH)D ≤90xa0nmol/l, an increase in PTH was observed. Adolescents are at risk for decreased serum 25(OH)D concentrations, especially black girls. We found that the widely used cutoff for vitamin D deficiency is associated with increasing PTH levels and is below the inflection point for a change in the slope of the regression line. Our results support the need for further research to establish optimal vitamin D status in adolescent girls.

Bone mineral density in adolescent females using injectable or oral contraceptives: a 24-month prospective study

OBJECTIVEnTo determine whether bone mineral density (BMD) is lower in hormonal-contraceptive users than in an untreated comparison group.nnnDESIGNnObservational, prospective cohort; 24-month duration.nnnSETTINGnAdolescent clinics in a metropolitan Midwestern setting.nnnPATIENT(S)nFour hundred thirty-three postmenarcheal girls, 12-18 years of age, who were on depot medroxyprogesterone acetate (DMPA; n = 58), were on oral contraceptives (OCs; n = 187), or were untreated (n = 188).nnnINTERVENTION(S)nDepot medroxyprogesterone acetate and OCs containing 100 microg of levonorgestrel and 20 microg of ethinyl E(2).nnnMAIN OUTCOME MEASURE(S)nMeasurements of BMD at spine and femoral neck were obtained by using dual x-ray absorptiometry at baseline and 6-month intervals.nnnRESULT(S)nOver 24 months, mean percentage change in spine BMD was as follows: DMPA, -1.5%; OC, +4.2%; and untreated, +6.3%. Mean percentage change in femoral neck BMD was as follows: DMPA, -5.2%; OC, +3.0%; and untreated, +3.8%. Statistical significance was found between the DMPA group and the other two groups. In the DMPA group, mean percentage change in spine BMD over the first 12 months was -1.4%; the rate of change slowed to -0.1% over the second 12 months. No bone density loss reached the level of osteopenia.nnnCONCLUSION(S)nAdolescent girls receiving DMPA had significant loss in BMD, compared with bone gain in the OC and untreated group. However, the clinical significance of this finding is mitigated by slowed loss after the 1st year of DMPA use and general maintenance of bone density values within the normal range in the DMPA group.

Sexual activity and other high-risk behaviors in adolescents with chronic illness: a review.

This article is a literature review of high-risk behaviors, including sexual activity, in adolescents with chronic illness. Three different models describing biopsychosocial constructs for risky behaviors are discussed. Regarding specific behaviors, findings from the literature include a substantial prevalence of sexual activity, but low level of knowledge and low prevalence of contraceptive use, in youth with chronic illness. Regarding substance use, alcohol was the most commonly used substance regardless of medical condition. Overall, substance use, as well as delinquent behavior, was lower among youth with chronic illness when compared to that in comparison groups. Results were mixed regarding the prevalence and determinants of unhealthy eating habits in these populations. Although high-risk behaviors in teenagers with chronic illness may be a normal part of development, awareness of their prevalence, along with early identification and counseling are important in order to anticipate adverse effects on their medical conditions.

Comparison of continuation rates for hormonal contraception among adolescents

BACKGROUNDnInadequate contraception is common among sexually active female adolescents, resulting in a high incidence of unwanted pregnancy. The authors were interested in comparing continuation rates for the different forms of hormonal contraception in this age group.nnnMETHODSnA retrospective chart review. The setting was an urban clinic in a large Midwestern city. Participants were 64% black, 34% white, and the average age was 15.5 years (+/- 1.6 SD), with implant users significantly older than oral contraceptive pill (OCP) users (P < .05). Interventions were self-selection to depo-medroxyprogesterone acetate (Depo-Provera; DMPA), levonorgestrel implants (Norplant), or oral contraceptive pills (OCPs). Previous pregnancy was significantly more prevalent in implant and DMPA users than in OCP users (P < .001). Over 4 years of follow-up, continuation rates were significantly higher for implant users than for the other hormonal groups (P < .001). At 1 year, continuation rates were as follows: 82% implants, 45% DMPA, and 12% OCPs. Combining these rates with those of the subsample who switched without interruption to another hormonal method, continued protection rates were much higher after 1 year: 96% implants, 83% DMPA, and 49% OCPs. Calculations of contraceptive restarts, i.e., hormonal method use in those who discontinued and then restarted after a gap of time, also increased to the prevalence of contraceptive protection.nnnCONCLUSIONnContinuation rates for levonorgestrel implants were significantly higher than those for DMPA and OCPs, the latter group having the lowest continuation rates. Factoring in switches and restarts to other hormonal methods further boosted the prevalence rates of contraceptive use in the adolescent population.

Recovery of bone mineral density in adolescents following the use of depot medroxyprogesterone acetate contraceptive injections

BACKGROUNDnDepot medroxyprogesterone acetate (DMPA) is a highly effective progestin-only contraceptive that is widely used by adolescents. We investigated bone mineral density (BMD) changes in female adolescents during and following use of this method.nnnSTUDY DESIGNnA multicenter, prospective, non-randomized observational study in 98 healthy female adolescents aged 12-18 years who initiated DMPA intramuscular injections for contraception and provided BMD data for up to 240 weeks while receiving DMPA and for up to 300 weeks after DMPA cessation. BMD at the lumbar spine (LS), total hip (TH) and femoral neck (FN) was assessed by dual-energy X-ray absorptiometry. A mixed model analysis of variance was used to examine BMD changes.nnnRESULTSnAt the time of their final DMPA injection, participants had mean BMD declines from baseline of 2.7% (LS), 4.1% (TH) and 3.9% (FN) (p<.001 at all three sites). Within 60 weeks of discontinuation of DMPA, mean LS BMD had returned to baseline levels, and 240 weeks after DMPA discontinuation, the mean LS BMD was 4.7% above baseline. Mean TH and FN BMD values recovered to baseline values more slowly: 240 weeks and 180 weeks, respectively, after the last DMPA injection.nnnCONCLUSIONSnBMD loss in female adolescents receiving DMPA for contraception is substantially or fully reversible in most girls following discontinuation of DMPA, with faster recovery at the LS than at the hip.

Knowledge, Attitudes And Behavior Related To Sexuality In Adolescents With Chronic Disability

This study explored the level of knowledge, attitudes and activity related to sexuality in a group of adolescents and young adults with myelomeningocele, a group of matched controls and a group of adolescents with cystic fibrosis. Slightly more than half of the study sample were female, the mean age was 17‐2 years, and their backgrounds were mainly middle‐class. 28 per cent of the myelodysplastic group reported previous sexual activity, compared with 60 per cent of the control group and 43 per cent of the group with cystic fibrosis. Most of the disabled adolescents expressed a desire to marry and have children, but fewer than 20 per cent had sought information regarding their sexual or reproductive function from their physician. Among those sexually active, 60 per cent of the controls and 67 per cent of those with cystic fibrosis had used contraception, compared with 16 per cent of the myelodysplastic group. The authors conclude that sex education and screening for contraceptive need is indicated for adolescents with chronic disabilities.

Adolescents: At Increased Risk for Osteoporosis?

Perhaps the most important factor in the primary prevention of osteoporosis is the attainment of an optimal peak bone during adolescence. In addition to endogenous factors, such as genetic and ethnic background, environmental factors such as dietary habits, physical activity, and sex hormone therapy, influence the accretion of bone mass during this critical period of skeletal growth. First, calcium dietary intake in adolescents is generally well less than the current recommended RDA of 1200 mg/day. Multiple studies of children and adolescents have demonstrated increases in bone mass with dietary calcium supplementation. Second, regarding physical activity, the overall impression is that a moderate amount of particularly weight-bearing exercise has a positive impact on bone. There appears, however, to be a threshold of intensity of physical activity over which a negative impact on bone occurs, particularly when the exercise is of an anaerobic nature or occurring in very thin, amenorrheic participants. Third, previous research suggests that the various forms of hormonal contraception exert differing effects on bone mass in adolescents, with levonorgestrel implants and combined oral contraceptives may be associated with a more positive effect on bone mass compared with that observed with depot medroxyprogesterone acetate. From a clinical perspective, approaches to optimizing peak bone mass in adolescents would include increasing calcium intake, whether in the form of dairy products, fortified foods, or supplements as well as encouraging participation at a moderate level, in weight-bearing exercise. Last, in adolescents with extensive risk factors and predicted long duration of use, subdermal implants or combined oral contraceptives may be the optimal hormonal methods of birth control.

The school breakfast program and cognition in adolescents

We studied cognitive function and metabolic status in a group of healthy adolescents fed the govermment supplied breakfast (n = 18) versus a control group (n = 16) fed a very low calorie meal. Serum glucose and β-hydroxybutyrate levels were repeatedly measured at predetermined intervals throughout the testing period. Acute cognitive and mood effect were evaluated in all subjects on a pre-post basis. No significant group differences emerged on a battery of psychological measures that assessed short-term auditory memory, vigilance, impulsivity, and mood. Neither serum glucose or β-hydroxybutyrate levels correlated significantly with any behavioral measure. Results are discussed in the context of previous studies of nutrition and cognition.

Early weight gain related to later weight gain in adolescents on depot medroxyprogesterone acetate.

OBJECTIVE: To examine whether early weight gain in adolescents on depot medroxyprogesterone acetate (DMPA) predicts continued excessive weight gain and identify risk factors of early weight gain. METHODS: Adolescents (n=97) initiating DMPA were eligible to participate. Height and weight were assessed at baseline and at 6, 12, and 18 months. Early weight gain was defined as more than a 5% weight gain after 6 months of DMPA use. Mean body mass index (BMI) at 6-month intervals was estimated based on early weight–gain status (5% or less gain compared with greater than 5% gain). Analysis of variance modeling was used to compare group BMI at each time point. Repeated-measures analysis of covariance modeling was used to explore the association between early weight gain and percentage change in BMI at 12 and 18 months of DMPA use. RESULTS: Twenty patients (21%) had early weight gain. Mean BMI for the 5% or less group and greater than 5% group was 23.4 and 24.5 (P=.31), 23.3 and 26.6 (P=.009), 24.2 and 28.7 (P=.007), and 25.7 and 32.1 (P=.01) at 0, 6, 12, and 18 months, respectively. Early weight gain was significantly associated with percentage change in BMI at 12 and 18 months (P<.001). No risk factors for early weight gain were identified. CONCLUSION: Adolescents who experience more than 5% weight gain after 6 months of DMPA use are at risk for continued excessive weight gain. Weight gain after 6 months on DMPA can be used to identify adolescents at risk for continued weight gain, and appropriate counseling can be done at this time point. LEVEL OF EVIDENCE: II

Reference values for bone mineral density in 12- to 18-year-old girls categorized by weight, race, and age.

Background: Normative bone mineral density (BMD) values for adults do not apply to the pediatric population because of dramatic and variable rates of bone mineral acquisition that take place throughout adolescence. Objective: This study was designed to provide normative BMD values for the lumbar spine and femoral neck by age, weight, and race in female adolescents for use by clinicians. Materials and methods: The study population comprised 422 healthy adolescent girls aged 12–18xa0years recruited from four primary-care clinics. BMD measurements were performed with dual-energy X-ray absorptiometry (DEXA). Results: The major statistical predictors of lumbar spine BMD and femoral neck BMD were race, chronological age, and weight. There was an increase in both lumbar spine and femoral neck BMD that paralleled an increase in age and weight. In addition, the lumbar spine BMD and the femoral neck BMD were higher in the black participants than in the non-black participants with mean BMD values in grams per centimeter squared of 1.02 and 0.98, respectively, for blacks and 0.96 and 0.89, respectively, for non-blacks (P<0.001). Conclusion: Our study produced the largest set of lumbar spine and femoral neck BMD normative values for female adolescents and confirms the importance of both demographic and anthropomorphic variables in determining normative BMD values.