Persistent asymptomatic isolated microscopic hematuria in Israeli adolescents and young adults and risk for end-stage renal disease

CONTEXT

Few data are available on long-term outcomes among adolescents and young adults with persistent asymptomatic isolated microscopic hematuria.

OBJECTIVE

To evaluate the risk of end-stage renal disease (ESRD) in adolescents and young adults with persistent asymptomatic isolated microscopic hematuria.

DESIGN, SETTING, AND PARTICIPANTS

Nationwide, population-based, retrospective cohort study using medical data from 1,203,626 persons aged 16 through 25 years (60% male) examined for fitness for military service between 1975 and 1997 were linked to the Israeli treated ESRD registry. Incident cases of treated ESRD from January 1, 1980, to May 31, 2010, were included. Cox proportional hazards models were used to estimate the hazard ratio (HR) of treated ESRD among those diagnosed as having persistent asymptomatic isolated microscopic hematuria.

MAIN OUTCOME MEASURES

Treated ESRD onset, defined as the date of initiation of dialysis treatment or the date of renal transplantation, whichever came first.

RESULTS

Persistent asymptomatic isolated microscopic hematuria was diagnosed in 3690 of 1,203,626 eligible individuals (0.3%). During 21.88 (SD, 6.74) years of follow-up, treated ESRD developed in 26 individuals (0.70%) with and 539 (0.045%) without persistent asymptomatic isolated microscopic hematuria, yielding incidence rates of 34.0 and 2.05 per 100,000 person-years, respectively, and a crude HR of 19.5 (95% confidence interval [CI], 13.1-28.9). A multivariate model adjusted for age, sex, paternal country of origin, year of enrollment, body mass index, and blood pressure at baseline did not substantially alter the risk associated with persistent asymptomatic isolated microscopic hematuria (HR, 18.5 [95% CI, 12.4-27.6]). A substantially increased risk for treated ESRD attributed to primary glomerular disease was found for individuals with persistent asymptomatic isolated microscopic hematuria compared with those without the condition (incidence rates, 19.6 vs 0.55 per 100,000 person-years, respectively; HR, 32.4 [95% CI, 18.9-55.7]). The fraction of treated ESRD attributed to microscopic hematuria was 4.3% (95% CI, 2.9%-6.4%).

CONCLUSION

Presence of persistent asymptomatic isolated microscopic hematuria in persons aged 16 through 25 years was associated with significantly increased risk of treated ESRD for a period of 22 years, although the incidence and absolute risk remain quite low.

Adolescent BMI trajectory and risk of diabetes versus coronary disease

BACKGROUND

The association of body-mass index (BMI) from adolescence to adulthood with obesity-related diseases in young adults has not been completely delineated.

METHODS

We conducted a prospective study in which we followed 37,674 apparently healthy young men for incident angiography-proven coronary heart disease and diabetes through the Staff Periodic Examination Center of the Israeli Army Medical Corps. The height and weight of participants were measured at regular intervals, with the first measurements taken when they were 17 years of age.

RESULTS

During approximately 650,000 person-years of follow-up (mean follow-up, 17.4 years), we documented 1173 incident cases of type 2 diabetes and 327 of coronary heart disease. In multivariate models adjusted for age, family history, blood pressure, lifestyle factors, and biomarkers in blood, elevated adolescent BMI (the weight in kilograms divided by the square of the height in meters; mean range for the first through last deciles, 17.3 to 27.6) was a significant predictor of both diabetes (hazard ratio for the highest vs. the lowest decile, 2.76; 95% confidence interval [CI], 2.11 to 3.58) and angiography-proven coronary heart disease (hazard ratio, 5.43; 95% CI, 2.77 to 10.62). Further adjustment for BMI at adulthood completely ablated the association of adolescent BMI with diabetes (hazard ratio, 1.01; 95% CI, 0.75 to 1.37) but not the association with coronary heart disease (hazard ratio, 6.85; 95% CI, 3.30 to 14.21). After adjustment of the BMI values as continuous variables in multivariate models, only elevated BMI in adulthood was significantly associated with diabetes (β=1.115, P=0.003; P=0.89 for interaction). In contrast, elevated BMI in both adolescence (β=1.355, P=0.004) and adulthood (β=1.207, P=0.03) were independently associated with angiography-proven coronary heart disease (P=0.048 for interaction).

CONCLUSIONS

An elevated BMI in adolescence--one that is well within the range currently considered to be normal--constitutes a substantial risk factor for obesity-related disorders in midlife. Although the risk of diabetes is mainly associated with increased BMI close to the time of diagnosis, the risk of coronary heart disease is associated with an elevated BMI both in adolescence and in adulthood, supporting the hypothesis that the processes causing incident coronary heart disease, particularly atherosclerosis, are more gradual than those resulting in incident diabetes. (Funded by the Chaim Sheba Medical Center and the Israel Defense Forces Medical Corps.).

Progression of normotensive adolescents to hypertensive adults: a study of 26,980 teenagers

Although prehypertension at adolescence is accepted to indicate increased future risk of hypertension, large-scale/long follow-up studies are required to better understand how adolescent blood pressure (BP) tracks into young adulthood. We studied 23 191 male and 3789 female adolescents from the Metabolic Lifestyle and Nutrition Assessment in Young Adults cohort (mean age: 17.4 years) with BP <140/90 mm Hg at enrollment or categorized by current criteria for pediatric BP and body mass index (BMI) values. Participants were prospectively followed up with repeated BP measurements between ages 25 and 42 years and retrospectively between ages 17 and 25 years for the incidence of hypertension. We identified 3810 new cases of hypertension between ages 17 and 42 years. In survival analyses, the cumulative risk of hypertension between ages 17 and 42 years was 3 to 4 times higher in men than in women. Using Cox regression models adjusted for age, BMI, and stratified by baseline BP, the hazard ratio of hypertension increased gradually across BP groups within the normotensive range at age 17 years, without a discernible threshold effect, reaching a hazard ratio of 2.50 (95% CI: 1.75 to 3.57) for boys and 2.31 (95% CI: 0.71 to 7.60) for girls in the group with BP at 130 to 139/85 to 89 mm Hg. BMI at age 17 years was strongly associated with future risk of hypertension even when adjusted to BP at age 17 years, particularly in boys. Yet, BMI at age 30 years attenuated this association, more evidently in girls. In conclusion, BP at adolescence, even in the low-normotensive range, linearly predicts progression to hypertension in young adulthood. This progression and the apparent interaction between BP at age 17 years and BMI at adolescence and at adulthood are sex dependent.

Reduced glucose effectiveness associated with reduced insulin release: an artifact of the minimal-model method

We previously demonstrated that minimal model-derived estimates of glucose effectiveness (SG), based on the frequently sampled intravenous glucose tolerance test (SGFSIGT), were reduced in islet-transplanted or streptozotocin-treated dogs and in patients with insulin-dependent diabetes mellitus. To ascertain the validity of our observations, we compared SGFSIGT with estimates based on a basal hormone replacement glucose clamp (SGBRCLAMP) and a basal hormone replacement glucose tolerance test (SGBRGTT) in normal control (CNTL, n = 12) and streptozotocin-treated dogs with normal fasting plasma glucose (STZ-Rx, n = 9). SGFSIGT was reduced in STZ-Rx compared with CNTL (P < 0.05). However, neither SGBRCLAMP nor SGBRGTT was reduced in the STZ-Rx group (P > 0.05). Comparison of protocols for each subject indicated that SGFSIGT was greater than either SGBRCLAMP or SGBRGTT in control (P < 0.002) but not in STZ-Rx dogs (P > 0.1). The relationship of SGFSIGT to insulin secretory function suggests that our previous conclusion that SGFSIGT was reduced in subjects with limited insulin release may be an artifact of the minimal-model method. Our results suggest that caution must be exercised in the interpretation of differences in minimal-model estimates of SG between subject groups with significantly different levels of insulin secretory function.