Search PubMed⌕ Search

Biomedical subjects

P Lichtenstein

Publications and source records attributed to P Lichtenstein.

59 records · Page 4Linked to original sources
PubMed1986

Calcium-regulating hormones and minerals from birth to 18 months of age: a cross-sectional study. II. Effects of sex, race, age, season, and diet on serum minerals, parathyroid hormone, and calcitonin.

The influence of sex, race, age, season, and diet (cow's milk formula v human milk) on serum minerals and calcium-regulating hormones in infants less than 18 months of age is described in this study of 198 infants. No sex differences were observed in calcium, magnesium, phosphorus, parathyroid hormone, or calcitonin concentrations. Black infants had decreased serum phosphorus concentrations compared with white infants. There was a decrease in serum ionized calcium and phosphorus levels with age. During winter, there were significant increases in serum calcium and magnesium and decreases in serum phosphorus, parathyroid hormone, and calcitonin levels. Formula-fed infants had increased serum phosphorus and decreased ionized calcium concentrations compared with infants fed human milk. Thus, race, age, season, and diet appear to exert significant effects on serum minerals and calcium-regulating hormones in infancy. Interpretation of these mineral and hormone concentrations in normal or diseased states should be based on normative data specific to race, age, season, and diet.

Age Factors↗
PubMedDate not supplied

Does genetic variance for cognitive abilities account for genetic variance in educational achievement and occupational status? A study of twins reared apart and twins reared together.

Studies of brothers and twins have shown that about 50 per cent of the variance in educational achievement and 40 per cent of the variance in occupational status reflects between-family variance. About half of the between-family variance for educational achievement and even more for occupational status is due to genetic effects and the remainder is due to sharing the same environment. With data on 35 pairs of male twins reared apart and 56 pairs reared together we investigated the extent to which genetic variance in SES can be attributed to genetic variance for cognitive abilities. For both educational achievement and occupational status there was significant genetic variance both in common with and independent of genetic variance for cognitive abilities. Thus, there are genetic effects contributing to familial similarity for SES that are not the same as those of importance for cognitive abilities. Candidate traits that may account for this remaining genetic variance in SES are personality, interests, or talents not represented in standard cognitive tests.

Achievement↗
PubMedDate not supplied

Genetic and environmental influences for type A-like measures and related traits: a study of twins reared apart and twins reared together.

The relative influences of genetic and environmental factors for Type A-like behaviors and related traits were examined in the Swedish Adoption/Twin Study of Aging. The sample consisted of 99 pairs of monozygotic twins separated at an early age and reared apart, 229 pairs of dizygotic twins reared apart, 160 monozygotic pairs reared together, and 212 dizygotic pairs reared together. The average age of the Swedish Adoption/Twin Study of Aging twins at the time of data collection in 1984 was 58.6 (SD 13.6); 72% of the pairs were over 50 years of age and 60% were female. The Framingham Type A Scale, three descriptors of the Type A behavior pattern (pressure, hard-driving, and ambitious), and measures of hostility and lack of assertiveness were assessed in a mailout questionnaire. Heritability (the proportion of total variance due to genetic effects) was 27%, 28%, 43%, 37%, 20%, and 12%, respectively, for the six measures. The most conservative test of significance indicated significant genetic influence for all but the hostility and assertiveness scales. Sharing the same rearing environment was generally unimportant for twin similarity in the Type A behaviors later in life; however, 20% of the variation in the hostility and assertiveness measures could be attributed to shared family environment. Evidence for the effects of correlated post-rearing environments was found for hostility. Approximately 60% of the variation in each of the measures can be attributed to non-shared environmental experiences unique to the individual.

Arousal↗
PubMedDate not supplied

Sex differences in the etiology of aggressive and nonaggressive antisocial behavior: results from two twin studies.

Recent theory and results from twin and adoption studies of children and adolescents suggest greater genetic influence on aggressive as compared to nonaggressive antisocial behavior. In addition, quantitative or qualitative differences in the etiology of these behaviors in males and females have been indicated in the literature. The Child Behavior Checklist was completed by the parents of 1022 Swedish twin pairs aged 7-9 years and of 501 British twin pairs aged 8-16 years. Genetic factors influenced aggressive antisocial behavior to a far greater extent than nonaggressive antisocial behavior, which was also significantly influenced by the shared environment. There was a significant sex difference in the etiology of nonaggressive antisocial behavior. Bivariate analyses supported the conclusion that the etiologies of aggressive and nonaggressive antisocial behavior differ for males and females.

Adolescent↗