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PubMed2006

II. Temporal patterns of longitudinal change in aging brain function.

Time-dependent changes in brain activity were assessed in a group of older adults who maintained good physical and cognitive health at years 1, 3, 5, 7, and 9 of the Baltimore Longitudinal Study of Aging neuroimaging study. Each year, these participants underwent PET scans during rest and delayed verbal and figural recognition memory conditions. While memory performance remained stable over the 8 years, both generalized and modality-specific patterns of time-dependent changes in regional cerebral blood flow (rCBF) were found. Many brain regions showed steady, progressive changes in rCBF over the 8 years while others maintained rCBF for a number of years before showing incremental declines or increases in activity. These temporal patterns of change were observed in many regions of the brain, particularly in the frontal and temporal lobes, suggesting that there are distinctive patterns of age-related functional decline and compensatory activity over time. The precise patterns of regional involvement and the temporal dynamics of rCBF change within specific regions vary based on cognitive processing demands.

Aged↗
PubMed1999

Longitudinal changes in serum 25-hydroxyvitamin D in older people.

Cross-sectional studies have suggested that serum 25-hydroxyvitamin D (25OHD) levels decline with aging. We have examined this putative decline in a longitudinal study using participants in the New Mexico Aging Process Study. 25OHD levels were measured in participants in whom serum samples were available between 1980 to 1982 and 1989 to 1994 (37 men and 99 women). The available data for these visits included age, gender, and the date the sample was obtained. Questionnaires assessing physical activity and vitamin D intake were administered at the visits. A seasonal variation (r = .25, P < .05) in 25OHD was demonstrated in the whole group of subjects. In 25 subjects who were not receiving vitamin D supplementation at either time and had samples obtained in the same season, both serum 25OHD (P < .05) and physical activity (P < .05) decreased over a mean period of 11.4 years. In 23 subjects who had samples obtained in the same season but used vitamin D supplements at both times, there was no change in serum 25OHD. Mean summer 25OHD levels did not change with the duration of study. On the other hand, the mean serum 25OHD declined with the duration of study when measured from winter to winter or spring to spring. Multiple regression analysis demonstrated that the month, activity level, vitamin D supplementation, and gender (P < .001) were independent determinants of serum 25OHD levels. This study confirms that aging is associated with a reduction in serum 25OHD, and suggests that this decrease is a reflection of reduced sun exposure rather than aging per se. The reduction in serum 25OHD was the result of decreasing winter and spring 25OHD serum concentrations. It is clear that vitamin D supplementation can prevent the age-related decline in 25OHD levels.

Aged↗
PubMed1992

Longitudinal changes in bronchial hyperresponsiveness in asthmatic and previously asthmatic children.

To determine if nonspecific bronchial hyperresponsiveness is present to the same degree in previously asthmatic children compared with currently asthmatic children, a longitudinal study was conducted. On the basis of a standardized respiratory questionnaire, 139 children from asthmatic families, between the ages of 6 and 21 years, were identified. Subjects had skin tests, a serum IgE level, and a methacholine challenge test. IgE and skin tests demonstrated atopy in both the previously and currently asthmatic children, which persisted over time. Bronchial hyperresponsiveness within the asthmatic children was not significantly different between visits. Previously asthmatic children did have significantly decreased airway hyperresponsiveness over time. Age did not affect the results of the bronchial hyperresponsiveness in the currently asthmatic children. Currently asthmatic children, however, were significantly more atopic when compared with previously asthmatic children at their initial evaluation. Currently asthmatic children were also more bronchial responsive and remained so over time. Bronchial hyperresponsiveness is persistent in children with current asthma symptoms.

Adolescent↗
PubMed2001

Longitudinal changes in reproductive hormones and menstrual cyclicity in cynomolgus monkeys during strenuous exercise training: abrupt transition to exercise-induced amenorrhea.

Cross-sectional studies of exercise-induced reproductive dysfunction have documented a high proportion of menstrual cycle disturbances in women involved in strenuous exercise training. However, longitudinal studies have been needed to examine individual susceptibility to exercise-induced reproductive dysfunction and to elucidate the progression of changes in reproductive function that occur with strenuous exercise training. Using the female cynomolgus monkey (Macaca fascicularis), we documented changes in menstrual cyclicity and patterns of LH, FSH, estradiol, and progesterone secretion as the animals developed exercise-induced amenorrhea. As monkeys gradually increased running to 12.3 +/- 0.9 km/day, body weight did not change significantly although food intake remained constant. The time spent training until amenorrhea developed varied widely among animals (7-24 months; mean = 14.3 +/- 2.2 months) and was not correlated with initial body weight, training distance, or food intake. Consistent changes in function of the reproductive axis occurred abruptly, one to two menstrual cycles before the development of amenorrhea. These included significant declines in plasma reproductive hormone concentrations, an increase in follicular phase length, and a decrease in luteal phase progesterone secretion. These data document a high level of interindividual variability in the development of exercise-induced reproductive dysfunction, delineate the progression of changes in reproductive hormone secretion that occur with exercise training, and illustrate an abrupt transition from normal cyclicity to an amenorrheic state in exercising individuals, that is not necessarily associated with weight loss.

Amenorrhea↗
PubMed2003

Longitudinal changes in growth parameters are correlated with changes in pulmonary function in children with cystic fibrosis.

OBJECTIVE: Nutritional status is associated with pulmonary health and survival in children with cystic fibrosis (CF). This study evaluated the weight gain pattern of children with CF in relation to the longitudinal trends of their pulmonary function. Our hypothesis was that children who experience continuous weight gain at a given rate will have better average forced expiratory volume in 1 second (FEV(1)) and change in FEV(1) than children who have weight gain patterns that deviate from this rate, even when total weight gain seems adequate. METHODS: Prospectively collected data were examined in 319 children, aged 6 to 8, who were routinely followed at the Minnesota Cystic Fibrosis Center. One to 67 measurements of weight (kg), height (cm), and FEV(1) (mL) were taken per child during this 2-year period. The data were analyzed by repeated measure regression analysis and by growth pattern analysis. RESULTS: At baseline, a 1-kg higher initial weight was associated with a 55-mL higher average FEV(1). During the follow-up period, a 1-kg gain in weight was associated with an increase in FEV(1) by 32 mL. Children who had a steady weight gain tended to experience greater increases in FEV(1) than children who experienced periodic losses in weight. CONCLUSIONS: We established that children who weigh more and who gain weight at an appropriate and uninterrupted rate have a better FEV(1) trajectory. Aggressive nutritional support to maintain growth in these children may therefore improve FEV(1), which can be taken as a surrogate for better lung health, and may ultimately lead to better survival.

Body Height↗
PubMed1989

[Study on the longitudinal changes of the dental caries attack patterns of young child patients in pedodontic clinic, School of Dentistry, Ohu University].

The status of dental caries prevalence in the child patients, having visited the pedodontic clinic of Ohu University Dental Hospital, was surveyed longitudinally for 2 years (between 3 and 5 years of age) or 3 years (between 2 and 5 years). Also the dental caries attack patterns used at the dental health examination in infants aged 3 years, were investigated longitudinally. The surveyed child patients were 132 boys and 143 girls who had 20 deciduous teeth in their mouth through the surveyed period. The results were as follows: 1. The dental caries prevalence rate in the child patients was high at each age. 2. B and C caries attack patterns showing extensive caries increased remarkably at 3 or 4 years of age, and O patterns decreased with advanced age. 3. The child patients having no change in the caries attack patterns for 3 years decreased about 70%, and the severe type group transmitted to C caries attack patterns increased with advanced age. 4. Most of O caries attack patterns at 2 years of age changed to other patterns between 3 and 4 years of age, and they were few at 5 years.

Child, Preschool↗
PubMed1998

Longitudinal changes in lung function associated with aspects of swine-confinement exposure.

Several aspects of swine-confinement farming appear to be leading to adverse respiratory effects. This study was set up in a longitudinal design to study the association between certain characteristics of farms or the way they are run and a decline in lung function. A cohort of 171 pig farmers was observed for 3 years. Lung function was measured. Exposure to farm characteristics was determined at the start of the observation period, using data from standardized farm surveys and from diaries kept by the participants. Mean decline in lung function was 73 mL/year for forced expiratory volume in 1 second (FEV1) and 55 mL/year for forced vital capacity (FVC). A longitudinal decline in FEV1 was significantly associated with the use of quaternary ammonium compounds as disinfectants (an additional 43 mL/year) and also with the use of an automated dry feeding system (an additional 28 mL/year). The association with the use of wood shavings as bedding material was not statistically significant. The impact of these characteristics in a longitudinal study provides stronger evidence for causal inference than that shown in previous cross-sectional designs. This may be useful in promoting preventive measures.

Adult↗
PubMed2005

Longitudinal changes in bone density in children and adolescents with moderate to severe cerebral palsy.

OBJECTIVE: To assess the natural history of "growth" in bone mineral density (BMD) in children and adolescents with moderate to severe cerebral palsy (CP). STUDY DESIGN: A prospective, longitudinal, observational study of BMD in 69 subjects with moderate to severe spastic CP ages 2.0 to 17.7 years. Fifty-five subjects were observed for more than 2 years and 40 subjects for more than 3 years. Each evaluation also included assessments of growth, nutritional status, Tanner stage, general health, and various clinical features of CP. RESULTS: Lower BMD z-scores at the initial evaluation were associated with greater severity of CP as judged by gross motor function and feeding difficulty, and with poorer growth and nutrition as judged by weight z-scores. BMD increased an average of 2% to 5%/y in the distal femur and lumbar spine, but ranged widely from +42%/y to -31%. In spite of increases in BMD, distal femur BMD z-scores decrease with age in this population. CONCLUSIONS: Children with severe CP develop over the course of their lives clinically significant osteopenia. Unlike elderly adults, this is not primarily from true losses in bone mineral, but from a rate of growth in bone mineral that is diminished relative to healthy children. The efficacy of interventions to increase BMD can truly be assessed only with a clear understanding of the expected changes in BMD without intervention.

Adolescent↗
PubMed2000

Longitudinal changes in bronchial responsiveness associated with swine confinement dust exposure.

STUDY OBJECTIVES: Acute exposure to the air in swine confinement units causes bronchial hyperresponsiveness and inflammation of the airways. This study was performed to assess the longitudinal development of bronchial responsiveness in pig farmers and to establish exposure-response relationships. METHODS: A cohort of 171 pig farmers was followed over a 3-year period. Bronchial responsiveness was assessed by a histamine provocation test. Long-term average exposure to inhalable dust and endotoxin was determined by personal monitoring in summer and winter, using data on farm characteristics and activities. Time-weighted average (TWA) personal exposure to ammonia was measured. Data on farm characteristics were gathered in the same period. RESULTS: Mean increase in responsiveness was 2.52 doubling concentrations of histamine for a 10% decrease in FEV(1) and 1.36 doubling concentrations for a 20% decrease in FEV(1). Long-term average exposure to dust was 2.63 mg/m(3) and to endotoxin was 105 ng/m(3). TWA exposure to ammonia was 1.60 mg/m(3). After adjusting for age and smoking behavior, long-term average exposure to inhalable dust was associated with increases in bronchial responsiveness expressed as steps for provocative concentration causing 10% fall in FEV(1). TWA exposure to ammonia, use of wood shavings as bedding, and automated dry feeding were associated with increases in responsiveness expressed as steps for provocative concentration causing a 20% fall in FEV(1). CONCLUSIONS: Exposure to dust and ammonia in pig farms contributes to chronic inflammation of the airways and should be reduced.

Adult↗
PubMedDate not supplied

Longitudinal changes in fatigue and energy during pregnancy and the postpartum period.

OBJECTIVE: To describe perceived levels of fatigue and energy before, during, and after pregnancy in a group of healthy women experiencing uncomplicated pregnancies; and to examine relationships between their perception of fatigue and energy, parity, and physiologic indicators of sleep disturbances, thyroid function, and iron deficiency. DESIGN: Prospective, longitudinal. SETTING: Participants' homes. PARTICIPANTS: Convenience sample of 24 primiparous and 1 8 multiparous women. MAIN OUTCOME MEASURES: Change in fatigue and energy over time. Measures were obtained at follicular and luteal phases of the menstrual cycle before pregnancy, at each trimester, and at 1 and 3 months after delivery. RESULTS: Younger age and lower prepregnancy levels of iron, ferritin, and hemoglobin explained 1st trimester fatigue. Less total sleep was related to fatigue in the 3rd trimester. Postpartum fatigue was related to reduced amounts of sleep and low levels of ferritin and hemoglobin. CONCLUSIONS: With the exception of premenstrual (luteal) fatigue, progesterone levels were unrelated to fatigue. Neither paid employment nor family variables influenced perception of fatigue. Nurses working with childbearing populations should counsel women about significant 1st trimester fatigue so they can prepare their work and home environments in an attempt to achieve adequate rest.

Adult↗
PubMed2005

Longitudinal change in 99mTcHMPAO cerebral perfusion SPECT in Parkinson's disease over one year.

BACKGROUND: Brain perfusion deficits have been reported previously in subjects with Parkinson's disease in comparison with healthy controls. OBJECTIVE: To carry out a longitudinal study of perfusion in patients with Parkinson's disease and controls to find areas showing a reduction in perfusion over one year. METHODS: Two HMPAO cerebral perfusion scans were acquired one year apart in 30 subjects with Parkinson's disease (mean (SD) age, 76 (5) years) and 34 healthy comparison subjects (76 (7) years). Scans were normalised to the mean intensity in the cerebellum. RESULTS: Using SPM99 within groups to investigate regions that showed a decrease in perfusion between scans, it was found that in Parkinson's disease subjects but not controls there was a significant cluster in the frontal lobe (Brodmann area 10) where perfusion decreased over the year. CONCLUSIONS: The progressive frontal perfusion deficits in Parkinson's disease are consistent with results from previous structural and neuropsychological studies suggesting frontal lobe involvement and executive dysfunction even in early Parkinson's disease.

Aged↗
PubMed2006

Longitudinal change in memory performance associated with HTR2A polymorphism.

We present a fresh approach to evaluating association with candidate genes and cognitive change by testing association for parameters describing individual growth curves from twins. Moderate genetic influences on memory in aging adults has been shown in quantitative genetic studies. A recently reported, association of a HTR2A polymorphism with episodic memory in young unrelated adults led us to investigate the association between a nearby polymorphism and longitudinal memory performance in the Swedish Adoption/Twin Study of Aging (SATSA). Analysis of growth curve parameters suggests that both how well individuals perform on figural memory at age 65 years and nonlinear change in figural memory performance across age are associated with HTR2A. Individuals with two copies of the common G allele demonstrated higher figural memory performance longitudinally than those with the less frequent A allele, with performance trajectories differing by 2-6% per year. These findings imply a role for the 5-HT2A serotonin receptor on the formation of episodic memories in older adults.

Age Distribution↗
PubMed2006

Longitudinal changes in peripheral refraction with age.

The changes in the patterns of refraction (skiagrams) over the central +/-35 degrees of the horizontal field of 3 originally near-emmetropic eyes of 2 subjects were determined over a time interval of 26 years. The subjects were aged 32 and 40 years at the time of the first measurements. The central refractions shifted in the expected hyperopic direction, while the radial and tangential image fields in the periphery became more myopic. These longitudinal results agree with recent transverse studies, provided that allowance is made for the change in central refraction: the reported loss with age in peripheral visual performance does not seem to be attributable to markedly increased peripheral astigmatism.

Adult↗
PubMed2000

Longitudinal changes in the ductus venosus, cerebral transverse sinus and cardiotocogram in fetal growth restriction.

OBJECTIVE: To evaluate the changes in flow velocity waveforms in the transverse cerebral sinus in growth-restricted fetuses and to correlate these changes with (1) flow velocity waveforms in the ductus venosus and (2) changes in computerized analysis of the fetal cardiotocogram. DESIGN: Fetuses between 22 and 37 weeks' gestation with an estimated fetal weight below the fifth centile were included in this prospective longitudinal study. Doppler measurements of the umbilical artery, descending aorta, middle cerebral artery, transverse cerebral sinus and ductus venosus were recorded. Fetal heart rate was analyzed by a computer system according to the Dawes-Redman criteria. RESULTS: We measured a significant correlation between pulsatility index in the cerebral transverse sinus and in the ductus venosus over the study period and at delivery. There was a negative correlation between these indices and short- and long-term variability of the fetal heart rate. There was a parallel increase in pulsatility in the ductus venosus and the transverse cerebral sinus. These changes were inversely correlated with fetal heart rate variability and preceded fetal distress. CONCLUSION: Cerebral venous blood flow in IUGR fetuses may be a useful additional investigation to discriminate between fetal adaptation and fetal decompensation in chronic hypoxemia.

Aorta↗