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Biomedical subjects

D S Freedman

Publications and source records attributed to D S Freedman.

At least 91 records · Page 5Linked to original sources
PubMed1986

Cigarette smoking initiation and longitudinal changes in serum lipids and lipoproteins in early adulthood: the Bogalusa Heart Study.

To examine the influence of cigarette smoking initiation on serum lipid and lipoprotein changes in early life, 747 nonsmoking 9- to 17-year-olds from the biracial community of Bogalusa, Louisiana were reexamined five to six years following an initial screening. Upon reexamination in 1981-1983, 147 reported smoking cigarettes (mean duration, 3.5 years; median number of weekly cigarettes, 20). Compared with nonsmokers, persons who began smoking had more unfavorable changes in serum triglycerides and lipoprotein cholesterol levels during follow-up, independently of age, sexual maturation, obesity, alcohol consumption, and oral contraceptive use in females. Smoking initiation was not associated with increases in serum total cholesterol levels, but compared with nonsmokers, white males and white females smoking three or more packs weekly showed additional mean increases of 13.2 and 11.6 mg/dl in low density lipoprotein cholesterol, additional 5.9 and 2.4 mg/dl increases in very low density lipoprotein cholesterol (VLDL-C), and additional decreases of 15.6 and 9.2 mg/dl in high density lipoprotein cholesterol levels, respectively. Black smokers showed larger increases in serum triglycerides and VLDL-C levels than did black nonsmokers. These findings indicate that the start of even modest cigarette smoking may have potentially long-term atherogenic effects. Prevention of smoking in early life should therefore be an important aspect of cardiovascular disease intervention.

Adolescent↗
PubMed1986

Racial (black-white) comparisons of the relationship of levels of endogenous sex hormones to serum lipoproteins during male adolescence: the Bogalusa Heart Study.

The cross-sectional relationship of endogenous androgens (testosterone, androstenedione, and dehydroepiandrosterone sulfate [DHEA-S]), estrogen (estradiol) and progestin (progesterone) to serum levels of lipoprotein cholesterol (very low-density [VLDL], low-density [LDL], and high-density lipoprotein [HDL]) and apolipoproteins (apo A-I and apo B) were studied in white (n = 251) and black (n = 258) adolescent boys, ages 11 to 17 years, as part of the Bogalusa Heart Study. Black boys had significantly higher levels of estradiol, HDL cholesterol, and apo A-I, and lower levels of androstenedione and VLDL cholesterol than white boys, independent of age and adiposity. Age was correlated strongly with testosterone and androstenedione, and moderately with DHEA-S and estradiol levels in both races. However, only in white boys was age consistently related to VLDL cholesterol (positively), HDL cholesterol (negatively), and apo A-I (negatively). Overall, testosterone was associated inversely with HDL cholesterol and apo A-I in white boys, while progesterone was related positively to apo A-I in both races after adjusting for age and adiposity. However, these relationships were found to differ with age. Partial correlations between levels of sex hormones and lipoproteins adjusted for age and adiposity showed no associations in the 11 to 12 year age group in boys of either race. A significant positive relation of testosterone to VLDL cholesterol, and inverse relations of testosterone to HDL cholesterol and apo A-I and DHEA-S to HDL cholesterol were apparent only in white boys in the 13 to 14 year age group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Persistence of high diastolic blood pressure in thin children. The Bogalusa Heart Study.

Relationships between initial anthropometric variables and subsequent diastolic blood pressure (fourth phase) were examined in children identified as being in the upper quintile for diastolic blood pressure at Year 1. Of 156 white children, aged 10 to 14 years, with diastolic blood pressure levels in the upper age-race-sex-specific quintile at Year 1, 38% remained in the upper quintile at Year 4. However, there was a definite trend for leaner children, defined by ponderosity (weight/height3) to remain in the highest diastolic blood pressure quintile (p less than 0.001). Of white children originally identified in the highest quintile for diastolic blood pressure and the lowest quintile for ponderosity (lean group), 67% (18 of 27) remained in the upper quintile at Year 4. In contrast, only 21% (11 of 52) of white children identified as being in the highest quintile for both diastolic blood pressure and ponderosity (obese group) at Year 1 were in the upper diastolic blood pressure quintile at Year 4. Similar results were seen in children examined 5 years later. Pearson correlation coefficients and linear regression analyses confirmed the negative relationship between initial ponderosity and subsequent diastolic blood pressure, especially in older children. A similar relationship was noted in black children. Potential differences in the etiological process of obesity-related and non-obesity-related high blood pressure were examined. These observations indicate that characteristics other than obesity can contribute to high blood pressure in late childhood.

Adolescent↗
PubMed1986

Serum apolipoproteins A-I and B in 2,854 children from a biracial community: Bogalusa Heart Study.

Serum apolipoprotein A-I (apo A-I) and apolipoprotein B (apo B) profiles were examined in 2,854 children, 5 to 17 years of age, from a total biracial community. Black boys had higher apo A-I levels than white boys (P less than .001), whereas girls showed no such race-related difference. Black-white difference in apo A-I persisted among boys with similar triglyceride levels provided that triglyceride levels were high. The ratio of high-density lipoprotein cholesterol (HDL-C)/apo A-I was higher in black than in white children, irrespective of sex (P less than .001). Only black children showed sex-related differences for apo A-I (boys greater than girls, P less than .05). Sex-related differences were seen in white children for HDL-C/apo A-I ratio (boys greater than girls, P less than .001) and in children of both races for apoB (girls greater than boys, P less than .01). Age-related changes were more apparent for apo A-I and HDL-C/apo A-I ratio than for apo B. A progressive decrease in apo A-I was noted during sexual maturation only in white boys. The magnitude of inverse association of apo B to HDL-C was less strong in black children (P less than .01). Although apo A-I was inversely correlated with very low-density lipoprotein cholesterol and triglycerides in white children, no association was noted in black children. These findings are indicative of intrinsic metabolic differences among the race-sex groups, resulting in variability in lipoprotein composition and levels and atherogenic potential.

Adolescent↗
PubMed1986

Value of childhood blood pressure measurements and family history in predicting future blood pressure status: results from 8 years of follow-up in the Bogalusa Heart Study.

The value of BP measurements and family history of cardiovascular disease in predicting future BP status was studied in 1,501 children, initially 2 to 14 years of age, who were examined four times during an 8-year period in the Bogalusa Heart Study. Correlation coefficients between year 1 and year 9 BPs were as follows for systolic and diastolic BPs, respectively: 0.41 and 0.35 (P less than .0001). These correlations were significant in all age groups. For children in the upper quartile of BP at any one prior examination, the percentage remaining in the year 9 upper quartile ranged from 41% to 52% for systolic BP and 35% to 44% for diastolic BP. Three serial BP measurements in the upper quartile increased the percentages remaining in the upper quartile to 68% for systolic BP and 62% for diastolic BP. Conversely, of those children not in the upper quartile of systolic BP at year 9, 96.8% did not have all three prior measurements in the upper quartile. Family history of hypertension was shown to independently predict year 9 systolic BP status. These results confirm the importance of serial BP measurements and family history of hypertension for the practicing physician.

Adolescent↗
PubMed1985

Relationship of changes in obesity to serum lipid and lipoprotein changes in childhood and adolescence.

To assess relationships between increases in triceps skin-fold thickness (TRSF) and changes in levels of serum lipids and lipoproteins in early life, a biracial sample of 1,598 five to 12 year olds were reexamined five years after an initial examination. Significant positive correlations, controlled for age, were observed between changes in TRSF and changes in levels of serum total cholesterol, serum triglycerides, and low- and very low-density lipoprotein cholesterol. Inverse associations between changes in TRSF and high-density lipoprotein cholesterol were weaker, but also statistically significant. Although females showed the largest increases in TRSF, most associations were stronger in males. Increases in estimated percentage body fat and ponderal index (kilograms per cubic meter) were highly associated with changes in TRSF, but showed slightly different associations with the serum lipids and lipoproteins. Results show that increases in obesity in youth are accompanied by an increasingly atherogenic lipoprotein profile.

Adolescent↗
PubMed1985

High density lipoprotein and coronary artery disease risk factors in children with different lipoprotein profiles: Bogalusa Heart Study.

Serum high density lipoprotein-cholesterol (HDL-C) and apoprotein A-1 (apo A-1) profiles were examined in subgroups of children (n = 338), initially aged 2-14 years, whose earlier beta-lipoprotein cholesterol (beta-LPC) and pre-beta-lipoprotein cholesterol (pre-beta-LPC) measurements were in extreme percentiles of values from a biracial community. Relationships of HDL-C and apo A-1 to serum lipoprotein lipids, apoprotein B (apo B), subscapular skinfold thickness, fasting and 1/2 hr postglucose plasma insulin, and fasting and 1 hr postglucose plasma glucose and free fatty acids were examined. Clustering of several coronary artery disease risk factors in these children was observed. HDL-C levels tended to be low in children having high pre-beta-LPC levels and apo A-1 levels were low in boys having high pre-beta-LPC levels. Within beta- and pre-beta-LPC strata, differences were also observed with respect to race, but not sex, in the mean levels of both HDL-C and apo A-1. HDL-C and apo A.1 were related inversely to subscapular skinfold thickness and plasma insulin levels in all children except those with low levels of both beta-LPC and pre-beta-LPC. Ratios of low density lipoprotein-cholesterol/HDL-C and of apo B/apo A-1 were related positively with other coronary artery disease risk factors except in children having low levels of both beta-LPC and pre-beta-LPC. The magnitude of these associations was greater in whites than in blacks. These observations may help to identify, at an early age, children at high risk of developing coronary artery disease in adulthood.

Adolescent↗
PubMed1985

Longitudinal serum lipoprotein changes in white males during adolescence: the Bogalusa Heart Study.

Determinants of follow-up levels of low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C) and the ratio of LDL-C to HDL-C were analyzed in a longitudinal study. White boys (n = 81) aged 11 to 12 years, when examined in 1973-1974 (year 1) were reexamined in 1978-1979 (year 6) at ages 16 to 17 years. During follow-up, mean levels of LDL-C increased from 87.6 mg/dL to 89.8 mg/dL, mean levels of HDL-C decreased from 67.0 mg/dL to 48.4 mg/dL and the mean LDL-C/HDL-C ratio increased from 1.45 to 2.12. Cross-sectional associations between the serum lipoproteins and weight, triceps skinfold thickness, and ponderosity (wt/ht3) were stronger in year 6 than in year 1. A persistence of ranks was observed between year 1 and year 6 for LDL-C (r = 0.61), HDL-C (r = 0.51), and LDL-C/HDL-C (r = 0.50). Multiple linear regression indicated that year 6 LDL-C levels were positively related to year 1 LDL-C, year 1 Tanner stage (an indication of sexual maturation), and the change in skinfold thickness during follow-up. Follow-up LDL-C/HDL-C was related both to change in height (negatively) and to change in weight (positively), after controlling for year 1 LDL-C/HDL-C. These longitudinal findings were similar to those obtained from earlier cross-sectional analyses and were further verified on an independent cohort of white boys also followed for five years (1976-1977 through 1981-1982).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Tracking of serum lipids and lipoproteins in children over an 8-year period: the Bogalusa Heart Study.

Although children initially identified as having elevated levels of coronary heart disease risk factors tend to have elevated follow-up levels (track), a substantial proportion show regression to the mean. Relationships of both genetic and environmental factors to tracking of serum lipids and lipoproteins over an 8-year period were examined in children from a biracial community. Associations between initial and follow-up levels were similar at 3, 5, and 8 years of follow-up; however, differences between the race-sex groups were observed. Two initial measurements reduced the number of nontrackers (children with high initial and decreased follow-up levels). Fathers of children showing persistently elevated levels of either serum total cholesterol or triglycerides were more likely to have diabetes mellitus or to have had heart attacks than were fathers of nontrackers. Children tracking for elevated low-density lipoprotein cholesterol levels had larger increases in triceps skinfold thickness than did the nontrackers. Children consuming alcohol tended to have elevated levels of high-density and decreased levels of low-density lipoprotein cholesterol at follow-up. These observations indicate that the use of repeated serum lipid and lipoprotein determinations, along with measurements of obesity and information concerning family history of heart attack and diabetes mellitus, can aid in the prediction of future elevated serum lipid and lipoprotein levels.

Adolescent↗
PubMed1985

The relationship between parental history of vascular disease and cardiovascular disease risk factors in children: the Bogalusa Heart Study.

The relationship between parental history of vascular disease (heart attack, stroke, diabetes mellitus, and hypertension) and risk factor variables for cardiovascular disease was assessed in 3,312 offspring aged 5-17 years during the 1981-1982 school year in the biracial community of Bogalusa, Louisiana. Risk factors studied included systolic blood pressure, diastolic blood pressure, serum total cholesterol, triglycerides, and individual lipoprotein cholesterol (beta-, low density lipoprotein (LDL) cholesterol; pre-beta, very low density lipoprotein (VLDL) cholesterol; and alpha-, high density lipoprotein (HDL) cholesterol). Risk factors were adjusted for age, race, sex, and height (blood pressure only) prior to testing parental history effects. Univariate comparisons between risk factors in children and vascular disease in parents resulted in statistically significant increases in systolic and diastolic pressures associated with the presence of maternal or paternal hypertension (p less than 0.001). Paternal heart attack was also associated with elevations in diastolic pressure (p less than 0.01) of children. Maternal diabetes mellitus was associated with an increase in serum total cholesterol (p less than 0.05). Paternal diabetes mellitus and maternal heart attack (for female progeny only) were associated with increases in mean triglyceride levels of children. VLDL cholesterol results were similar to those for triglycerides. For HDL cholesterol, paternal diabetes mellitus was associated with a small decrease in mean levels (p less than 0.05). Dramatic increases to the highest decile of risk were found in association with the following parental disease combinations: paternal heart attack-paternal diabetes for serum total cholesterol (p less than 0.0001), maternal heart attack-paternal diabetes (p less than 0.001) and paternal stroke-maternal diabetes (p less than 0.0001) for LDL cholesterol. Multivariate analysis detected no significant effects of single parental vascular disease. However, paternal heart attack in combination with either diabetes mellitus or hypertension was statistically significant in their relationship to the risk factors overall.

Adolescent↗
PubMed1984

Further reflections on changes in fertility expectations and preferences.

In this paper we have shown that the statements made in our original paper and disputed by Sloane and Lee are not ". . . . .at least partially in error." Concerning the first two areas of disagreement, Sloane and Lee's analysis did not address the conclusions that we reached and, therefore, could not refute them. In the first instance the observations of Sloane and Lee are useful in understanding how one of the effects we observed occurred, but in the second area the usefulness of their analysis is not at all clear. The third area of disagreement resulted because Sloane and Lee paid insufficient attention to the observed sample relationships and used a statistical test that is inefficient for the type of data used. Of course, our disagreement is not with log-linear methodology, but with its inappropriate application and interpretation by Sloane and Lee. In two instances they used results from the log-linear procedures to address issues that could not be addressed by those particular results, and in another instance they used a log-linear test of statistical significance when a more efficient alternative provides a different picture. The problems associated with the Sloane and Lee analysis illustrate the importance of precise specification of the substantive issues being investigated and the careful interpretation of the substantive implications of the original data and statistical results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Income and fertility: the elusive relationship.

This paper uses longitudinal data for 1962-1977 to examine the relationship of husband's income to 1962 expected fertility to final parity, and to the discrepancy between initial expectations and final parity, separately for four groups of women who in 1962 either had just given birth to a first, second, or fourth child or had just been married. Although economic reasons frequently were cited in 1977 for downward revisions in family size goals, husband's income was not positively related to fertility in three of the four parity groups. For the merged sample, excluding women with unwanted births, husband's income showed a small positive relationship to completed fertility.

Family Characteristics↗
PubMed1980

Changes in fertility expectations and preferences between 1962 and 1977: their relation to final parity.

Changing fertility expectations and preferences from 1962 to 1977 are compared with final parity in a longitudinal study. Results are strongly affected by initial parity in 1962. Final parity, 27 percent below expectations for those initially childless, illustrates the effect for couples free to change expectations downward of declining fertility preferences. Changes in expectations early in marriage had a significant long-term effect on final parity, as did early differences between wife's expectations and husband's preferences. unplanned births increased final parity significantly. Religion, education, and income had no systematic relation to the discrepancy between initial expectations and final parity.

Family Characteristics↗
PubMed1973

The reproducibility and use of the tritiated folic acid urinary excretion test as a measure of folate absorption in clinical practice: effect of methotrexate on absorption of folic acid.

Investigations into the standardization and reproducibility of the urinary excretion method for determining the absorption of tritiated folic acid were carried out. By proper timing of tissue-loading doses of folic acid a clear difference between the percentage excretion ranges of normal and coeliac subjects was obtained. In addition conditions were found whereby the procedure could be repeated on an individual up to four times with reproducible results. Methotrexate in pharmacological amounts was found to have no inhibitory effect on the human intestinal absorption of a small oral dose (300 mug) of folic acid as determined by this method. This indicates that reduction of folic acid is not necessary for its absorption in man.

Administration, Oral↗