Disruption of the relationship between fat content and leptin levels with aging in humans

Leptin released from adipose tissue is believed to participate in a negative feedback loop regulating appetite, and malfunction of this mechanism could lead to obesity. We measured plasma leptin and body composition (dual energy x-ray absorptiometry) in 70 healthy subjects, divided into 3 age groups (young, 25 +/- 1 yr; middle-aged, 53 +/- 1 yr; old, 70 +/- 1 yr), while on a 5-day weight-maintaining diet. Pairwise correlations were assessed using product-moment correlation, and regression analysis was used to evaluate relationships between leptin and other variables. Leptin concentrations and relative body fat content were correlated in young females (r = 0.71; P = 0.009) and in young males (r = 0.76; P = 0.007), but not in the combined middle-aged and elderly groups (r = 0.19; P = 0.36 and r = 0.19; P = 0.38 in females and males, respectively). Regression analysis showed a clear correlation between circulating leptin and relative fat mass in the young subjects (P = 0.0001), but not in the older subjects (P = 0.199). We conclude that body fat content in young subjects correlates with plasma leptin in both genders, whereas this relationship is disrupted in elderly subjects, thus possibly contributing to the obesity occurring with age.     

A prospective study of age differences in consequences of emotional control in women referred to clinical mammography.

Age differences in emotional control and their consequences were examined in women referred to mammography on the suspicion of breast cancer but with benign results of the examination. Under natural experimental conditions, the levels of emotional control and distress were measured 1 week prior to the examination as well as 4 and 12 weeks after the examination in 717 younger women (ages 19–39), middle-aged women (ages 40–59), and older women (ages 60–85). A higher level of emotional control was found in the older women; this indicates that, in these birth cohorts, emotion-focused coping is more prevalent in old age than in young adulthood, even when similar stressors are experienced. The analyses revealed an interaction between age and emotional control; higher levels of control were related to a reduction in distress during the course of the study in older women, whereas emotional control was unrelated to changes in distress in younger and middle-aged women. The findings support the life span theory of control, which suggests that secondary control strategies are more adaptive in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in memory for prose: The question of sensitivity to passage structure.

The hypothesis that older adults remember prose less well than young adults because they are less sensitive to the structure of prose passages was investigated in three experiments. In Experiments 1 and 2, older adults (aged 54–85) recalled less information than younger ones (aged 20–36) from stories having various structures, but there was no evidence that older people were insensitive to story structure. The pattern of recall of information high and low in the story structure was similar for young and old for each story examined. Experiment 3 extended the findings to recall of full-length essays and their summaries. These results suggest that the old are as sensitive to passage structure as the young. In addition, comparisons across the three experiments suggest that other frequently invoked explanations of age deficits in prose recall, such as individual differences in verbal ability and the nature of the materials used, cannot explain our results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehension of pronouns in young and older adults.

Explored, in 3 experiments, the issue of whether young (19–37 yrs old) and older (57–84 yrs old) adults differ in their use of pragmatic information in anaphor resolution. 64 Ss from each age group were required to select the antecedent for the pronoun he in sentence pairs such as "Henry spoke at a meeting while John drove to the beach. He brought along a surfboard." Results indicate that young and older Ss were equally influenced by contextual constraints in choosing pronoun referents when the sentence containing the pronoun followed immediately after the context-setting sentence. When extraneous material intervened, however, both age groups became less consistent in their pronoun choices, with older Ss being more affected. Evidence is presented that the failure to use pragmatic constraints in pronoun assignment resulted from inability to recall the relevant contextual information. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creatine supplementation and age influence muscle metabolism during exercise

Young [n = 5, 30 +/- 5 (SD) yr] and middle-aged (n = 4, 58 +/- 4 yr) men and women performed single-leg knee-extension exercise inside a whole body magnetic resonance system. Two trials were performed 7 days apart and consisted of two 2-min bouts and a third bout continued to exhaustion, all separated by 3 min of recovery. 31P spectra were used to determine pH and relative concentrations of Pi, phosphocreatine (PCr), and beta-ATP every 10 s. The subjects consumed 0.3 g . kg-1 . day-1 of a placebo (trial 1) or creatine (trial 2) for 5 days before each trial. During the placebo trial, the middle-aged group had a lower resting PCr compared with the young group (35.0 +/- 5.2 vs. 39.5 +/- 5.1 mmol/kg, P < 0.05) and a lower mean initial PCr resynthesis rate (18.1 +/- 3.5 vs. 23.2 +/- 6.0 mmol . kg-1 . min-1, P < 0.05). After creatine supplementation, resting PCr increased 15% (P < 0.05) in the young group and 30% (P < 0.05) in the middle-aged group to 45.7 +/- 7.5 vs. 45.7 +/- 5.5 mmol/kg, respectively. Mean initial PCr resynthesis rate also increased in the middle-aged group (P < 0.05) to a level not different from the young group (24.3 +/- 3.8 vs. 24.2 +/- 3.2 mmol . kg-1 . min-1). Time to exhaustion was increased in both groups combined after creatine supplementation (118 +/- 34 vs. 154 +/- 70 s, P < 0.05). In conclusion, creatine supplementation has a greater effect on PCr availability and resynthesis rate in middle-aged compared with younger persons.     

Relationships among age, conditioned stimulus–unconditioned stimulus interval, and neuropsychological test performance.

To evaluate the effect of age at various conditioned stimulus (CS)–unconditioned stimulus (US) intervals, 144 young, middle-aged, and older adults were tested on eyeblink classical conditioning at CS–US intervals of 500, 1,000, or 1,500 ms. Reaction time, response timing, motor learning, declarative memory, and attention were assessed to identify correlates of conditioning at various CS–US intervals. Previously reported middle-aged and older adults were impaired at a 400-ms CS–US interval, but the addition of 100 ms to the CS–US interval in this study enabled equal conditioning in middle-aged and young adults. At a 1,000-ms CS–US interval, older adults remained significantly impaired. It was only at the 1,500-ms CS–US interval that conditioning was equal for the 3 age groups. Measures of reaction time, timing, and motor learning were not correlated systematically with conditioning. Whereas the results of age differences at various CS–US intervals were clear and striking, patterns of relationships among neuropsychological and conditioning variables were not consistent in indicating sources of age differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of adult age on primary and secondary memory search.

Conducted 2 experiments with 25 19–29 yr olds, 26 62–85 yr olds, 30 18–32 yr olds, and 30 61–81 yr olds to compare young and elderly adults on the ability to search lists of words stored in primary memory (PM) and in secondary memory (SM). Exp I indicated that age differences in search performance were greatest under SM conditions. Older Ss, unlike the younger ones, appeared biased toward responding that probe items were not members of the memory sets stored in SM. As a result of this apparent bias, older Ss committed a large number of errors on trials in which the probe was a member of the memorized list (i.e., positive probe trials) yet few errors on the trials in which the probe was not a member of the list ( i.e., negative probe trials). The responses of older Ss to negative probe trials were more rapid than were those to positive probe trials. In Exp II, this pattern of responding was examined. It is concluded that age differences were involved in the ability to encode memory sets and transfer them from PM to SM as well as in the ability to retrieve information from SM prior to conducting a memory search. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memorizing while walking: Increase in dual-task costs from young adulthood to old age.

The dual task of memorizing word lists while walking was predicted to become more difficult with age because balance and gait are in greater need of "attentional resources." Forty-seven young (ages 20–30 years), 45 middle-aged (40–50), and 48 old (60–70) adults were trained to criterion in a mnemonic technique and instructed to walk quickly and accurately on 2 narrow tracks of different path complexity. Then, participants encoded the word lists while sitting, standing, or walking on either track; likewise, speed and accuracy of walking performance were assessed with and without concurrent memory encoding. Dual-task costs increased with age in both domains; relative to young adults, the effect size of the overall increase was 0.98 standard deviation units for middle-aged and 1.47 standard deviation units for old adults. It is argued that sensory and motor aspects of behavior are increasingly in need of cognitive control with advancing age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pretherapy orientation as preparation for open psychotherapy groups.

Compared 20 14–47 yr old psychiatric outpatients who received an orientation program before entering open psychotherapy groups with 20 15–58 yr old psychiatric patients (control group) who received no orientation in an investigation of the effectiveness of pretherapy orientation. Orientation was presented on an individual basis and consisted of an instructional lecture-discussion followed by a videotape of a simulated group session, with patient participation solicited throughout the presentation. Dependent measures included dropout and attendance rates, a self-report symptom inventory, and a therapist rating scale. Results show that mean attendance rates for the 1st 10 group sessions were significantly higher for the orientation group. The control group exhibited significantly greater audience-seeking behavior on the 3rd-session therapist ratings. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concomitant eyeblink and heart rate classical conditioning in young, middle-aged, and elderly human subjects.

Pavlovian heart rate (HR) and eyeblink (EB) conditioning were assessed in 4 groups of Ss who differed in age: young?=?19–33 yrs, young middle-aged?=?35–48 yrs, old middle-aged?=?50–63 yrs, and old?=?66–78 yrs. A 100-msec corneal airpuff was the unconditioned stimulus/stimuli (UCS) and a 600-msec tone was the CS. A nonassociative control group received explicitly unpaired tone and airpuff presentations. All Ss were studied for 2 100-trial sessions separated by approximately 7 days. An impairment in acquisition of both the EB and HR responses occurred in the old and middle-age Ss, but all age groups showed significantly greater conditioning than did the control group. Slight increases in performance resulted from a 2nd session of training. These findings suggest and age-related impairment in a general associative process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An examination of the applicability of the Substance Abuse Proclivity Scale to young adult males.

The substance abuse proclivity (SAP) scale, which was derived from the Minnesota Multiphasic Personality Inventory (MMPI) for use with young (16–21 yr old) males, was applied to samples of 69 young adult male substance abusers, 51 college students, 26 psychiatric outpatients, and 1,298 medical outpatients (all Ss aged 20–29 yrs). Analyses demonstrated that the validity shrinkage was very modest when the scale was applied to Ss of this older age range. The correlation between age and SAP scale score was both significant and negative for 363 independently identified substance abusers (aged 13–26 yrs), which suggests that the scale taps something more basic than the accumulated consequences of the chronic use of substances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in big five behavior averages and variabilities across the adult life span: Moving beyond retrospective, global summary accounts of personality.

In 3 intensive cross-sectional studies, age differences in behavior averages and variabilities were examined. Three questions were posed: Does variability differ among age groups? Does the sizable variability in young adulthood persist throughout the life span? Do past conclusions about trait development, based on trait questionnaires, hold up when actual behavior is examined? Three groups participated: young adults (18–23 years), middle-aged adults (35–55 years), and older adults (65–81 years). In 2 experience-sampling studies, participants reported their current behavior multiple times per day for 1- or 2-week spans. In a 3rd study, participants interacted in standardized laboratory activities on 8 occasions. First, results revealed a sizable amount of intraindividual variability in behavior for all adult groups, with average within-person standard deviations ranging from about half a point to well over 1 point on 6-point scales. Second, older adults were most variable in Openness, whereas young adults were most variable in Agreeableness and Emotional Stability. Third, most specific patterns of maturation-related age differences in actual behavior were more greatly pronounced and differently patterned than those revealed by the trait questionnaire method. When participants interacted in standardized situations, personality differences between young adults and middle-aged adults were larger, and older adults exhibited a more positive personality profile than they exhibited in their everyday lives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of aging on the sensitivity of growth hormone secretion to insulin-like growth factor-I negative feedback

To determine the effect of aging on the suppression of GH secretion by insulin-like growth factor (IGF)-I, we studied 11 healthy young adults (6 men, 5 women, mean +/- SD: 25.2 +/- 4.6 yr old; body mass index 23.7 +/- 1.8 kg/m2) and 11 older adults (6 men, 5 women, 69.5 +/- 5.8 yr old; body mass index 24.2 +/- 2.5 kg/m2). Saline (control) or recombinant human IGF-I (rhIGF-I) (2 h baseline then, in sequence, 2.5 h each of 1, 3, and 10 micrograms/kg.h) was infused iv during the last 9.5 h of a 40.5-h fast; serum glucose was clamped within 15% of baseline. Baseline serum GH concentrations (mean +/- SE: 3.3 +/- 0.7 vs. 1.9 +/- 0.5 micrograms/L, P = 0.02) and total IGF-I concentrations (219 +/- 15 vs. 103 +/- 19 micrograms/L, P < 0.01) were higher in the younger subjects. In both age groups, GH concentrations were significantly decreased by 3 and 10 micrograms/kg.h, but not by 1 microgram/kg.h rhIGF-I. The absolute decrease in GH concentrations was greater in young than in older subjects during the 3 and 10 micrograms/kg.h rhIGF-I infusion periods, but both young and older subjects suppressed to a similar GH level during the last hour of the rhIGF-I infusion (0.78 +/- 0.24 microgram/L and 0.61 +/- 0.16 microgram/L, respectively). The older subjects had a greater increase above baseline in serum concentrations of both total (306 +/- 24 vs. 244 +/- 14 micrograms/L, P = 0.04) and free IGF-I (8.5 +/- 1.4 vs. 4.2 +/- 0.6 micrograms/L, P = 0.01) than the young subjects during rhIGF-I infusion, and their GH suppression expressed in relation to increases in both total and free serum IGF-I concentrations was significantly less than in the young subjects. We conclude that the ability of exogenous rhIGF-I to suppress serum GH concentrations declines with increasing age. This suggests that increased sensitivity to endogenous IGF-I negative feedback is not a cause of the decline in GH secretion that occurs with aging.     

Age Differences in Everyday Problem-Solving and Decision-Making Effectiveness: A Meta-Analytic Review.

The authors report a meta-analysis of age differences in everyday problem-solving/decision-making effectiveness (EPSE). Effect sizes were calculated to reflect 3 age group comparisons: old versus young, young versus middle-aged, and middle-aged versus old. Findings from the meta-analysis of 28 separate studies with an aggregate of 4,482 participants do not support theories of preserved EPSE in late adulthood. Although significant age differences of moderate magnitude persisted across methodological and theoretical domains, rating criteria (experimenter vs. participant) emerged as a significant moderator of the effect magnitude and direction. In addition, EPSE in older adults was bolstered when problem content was interpersonal and when samples were highly educated. Finally, the current results support the conceptual integration of findings from the everyday problem-solving and everyday decision-making literatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Signaling techniques that increase the understandability of expository prose.

In 2 experiments, 102 15–17 yr old high school students read and listened to either a signaled or nonsignaled expository passage. The signals consisted of preview sentences, underlined headings, and logical connective phrases. The results show a pattern in which the signaled groups performed better on recall of conceptual information and on generating high quality problem solutions, whereas the nonsignaled groups excelled on recall of information from the beginning and end of the passage and on generating low quality problem solutions. These results suggest that signaling is effective in modifying students' reading strategies. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of age on consistent and varied semantic-category search performance.

Three experiments examined age-related consistent mapping (CM) and varied mapping (VM) practice effects. In separate experiments, young (age, 19–22), middle-aged (37–50), and older (64–88) adults' performance was examined using semantic-category and letter-based search paradigms. After extensive practice, major age differences occurred in CM search. Young and middle-aged subjects showed near-zero comparison slopes, large reductions in mean reaction times, and substantial reductions in response variability. Although older adults' reaction time decreased with CM practice, the reduction in reaction time, comparison slope, and response variability was small compared with the other groups. In VM search, older subjects were slower than the other age groups, but all groups exhibited similar linear set-size functions, search termination, and comparison-load effects. We concluded that age-associated declines in cognitive performance may be due in large part to the degree with which older adults can acquire or use automatic processes to perform tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A social-behavioral analysis of skill deficits in delinquent and nondelinquent adolescent boys.

Developed a measure consisting of 44 behavioral role-playing and problem-solving items, the Adolescent Problems Inventory (API), along with an item-specific criterion-referenced raters' manual, to identify strengths and weaknesses in the personal and interpersonal skills repertoires of adolescent boys. In an initial validation study, the API responses of institutionalized delinquent boys were rated as less competent than the responses of either of 2 nondelinquent groups of teenage boys ("good citizens" and "leaders") from a public high school. There were 20 14.1–27.9 yr old Ss in each group. Analyses of the inventory's characteristics showed it to be reliable, to be composed of items with little or no cluster structure, and to have extraordinary discriminant power. Two other validation studies compared the API responses of 15 14–27 yr old institutionalized delinquent boys who had frequent behavioral problems within the institution with 15 institutionalized delinquent boys who had few acting-out problems, and group differences between 40 16–27 yr old delinquents and 40 carefully matched nondelinquents. The type of directions given and test format significantly affected performance. It is suggested that researchers using a social skills conceptualization of personality do more thorough assessment studies of behavior pathologies before embarking on the development of large-scale social skills training programs. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coping with chronic illness: A study of illness controllability and the influence of coping strategies on psychological adjustment.

Longitudinal data on the coping strategies used by 151 41–89 yr old middle-aged and older adults faced with 1 of 4 chronic illnesses were used to evaluate the role of coping in the explanation of psychological adjustment. The authors distinguished between illnesses that offer few opportunities for control (rheumatoid arthritis and cancer) and those more responsive to individual and medical efforts at control (hypertension and diabetes) and evaluated the emotional consequences of 2 coping strategies—information seeking and wish-fulfilling fantasy—expected to play different roles in adjustment. Results show that information seeking had salubrious effects on adjustment and that wish-fulfilling fantasy had deleterious consequences; contrary to expectation, neither strategy's effects were modified by illness controllability. Analyses of the direction of causation between coping and adjustment suggest that wish-fulfilling fantasy is linked to poor adjustment in a mutually reinforcing causal cycle. The modesty of the effects of coping, however, demands replication of results to confirm the conclusions drawn in the present study. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)