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Biomedical subjects

T Rönnemaa

Publications and source records attributed to T Rönnemaa.

At least 19 recordsLinked to original sources

Association between serum lipids and apolipoprotein E phenotype is influenced by diet in a population-based sample of free-living children and young adults: the Cardiovascular Risk in Young Finns Study.

Apolipoprotein E (apoE) is a genetic determinant of coronary heart disease and lipid levels in several populations. We studied whether the association of apoE alleles with serum lipids varies with diet in a population of free-living young Finns. One thousand twelve subjects, aged 9-24 years, were studied as a part of the Cardiovascular Risk in Young Finns Study in 1986. Serum lipid concentrations and apoE phenotypes were determined, and the composition of the diet was assessed by the 48-h recall method. The subjects were divided into three groups according to the intake of dietary saturated fatty acids (SAFA, g/1000 kcal) and cholesterol (mg/1000 kcal). Group one (high SAFA-cholesterol group) was formed from subjects belonging to the highest tertiles of both cholesterol and SAFA intakes (n = 175); group two (middle SAFA-cholesterol group) consisted of subjects belonging to the middle respective tertiles (n = 119); and group three (low SAFA-cholesterol group) consisted of subjects belonging to the lowest respective tertiles (n = 192). The statistical significance of the association of serum total cholesterol and low density lipoprotein (LDL) concentration with apoE phenotype increased from the low SAFA-cholesterol group (P = 0.024 for total cholesterol and P = 0.015 for LDL-cholesterol, respectively) to the high SAFA-cholesterol group (P = 0.0022 and P = 0.00073, respectively). The middle SAFA-cholesterol group fell between these two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Clustering and six year cluster-tracking of serum total cholesterol, HDL-cholesterol and diastolic blood pressure in children and young adults. The Cardiovascular Risk in Young Finns Study.

Clustering and tracking of serum total cholesterol, high-density lipoprotein cholesterol (HDL-C) and diastolic blood pressure were studied in children and young adults. "High-risk" individuals were defined as those having these risk factors at the age and sex specific upper tertile (lowest tertile for HDL-C). Among older boys risk factors occurred at adverse levels more often than expected by chance. Cluster-tracking was assessed as the probability of remaining in the extreme tertiles during follow-up. Approximately 25% of subjects initially at "risk" remained there for 6 years. Subjects who became high-risk individuals during the follow-up expressed greater increase in obesity indices, started to consume more saturated fat and cholesterol and became physically active less often compared to those subjects who were initially at risk, but no longer at the follow-up.

Adolescent

Prevalence of isthmic lumbar spondylolisthesis in middle-aged subjects from eastern and western Finland.

Isthmic spondylolisthesis of the lumbosacral spine is a common radiologic finding in patients with low back pain, but its prevalence in unselected populations is poorly known. We examined X-ray pictures of the lumbosacral region of 1147 randomly selected 45-64-yr-old subjects living in eastern or western Finland. Of them, 69 subjects were found to have isthmic spondylolisthesis. The finding was more common in men (7.7%) than in women (4.6%; p = 0.026). The prevalence of spondylolisthesis was not age-related; it was higher in women with an occupation causing a high back load than in those with a low load occupation (p = 0.049), but this difference was not seen in men. The prevalence of spondylolisthesis tended to be higher in women with multiple pregnancies than in those with less than or equal to 2 pregnancies (p = 0.074). Women from eastern Finland had a higher prevalence of spondylolisthesis (7.2%) than those from western Finland (2.6%; p = 0.007), whereas no such difference was seen in men. The difference in women may partly be explained by factors causing loading of the low back, i.e. heavier work and a higher number of pregnancies.

Female

Coronary heart disease risk factors before and after bypass surgery: results of a controlled trial on multifactorial rehabilitation.

The effect of a three-phase multifactorial institution-based rehabilitation programme on coronary heart disease (CHD) risk factors was studied in an open randomised trial comprising 228 patients undergoing coronary artery bypass surgery allocated into a rehabilitation (R) group (n = 119) and a hospital (H = control) group (n = 109). Follow-up examinations were performed at 6 and 12 months. Serum total cholesterol and triglyceride levels decreased significantly in both groups during follow-up. These decreases were not significantly different between the R and H groups. Serum high density lipoprotein (HDL) cholesterol level increased significantly at 6 and 12 months in the R group, but not in the H group. The differences in the changes between the groups were not significant. The ratio of serum HDL cholesterol to total cholesterol increased significantly in the R group from the preoperative value of 0.154 to 0.179 (P less than 0.001) at 6 months and to 0.180 (P less than 0.001) at 12 months. In the H group these values were 0.152, 0.166 (P less than 0.001) and 0.168 (P less than 0.001), respectively. The significance of the differences in the changes between the groups were P = 0.01 at 6 months and 0.06 at 12 months. These differences were more obvious in patients aged 55 years or under. There was a significant decrease (P = 0.005) in the proportion of smokers in the R group and a significant increase in the proportion of patients taking regular exercise in both groups as assessed by questionnaire.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists

Responses of atrial natriuretic factor to long-term sodium restriction in mild to moderate hypertension.

The effects of long-term sodium restriction on plasma atrial natriuretic factor (ANF) concentrations, and the role of baseline plasma ANF concentration as an indicator of changes in haemodynamics and left ventricular hypertrophy during this treatment were studied in 40 middle-aged previously untreated mildly to moderately hypertensive men and women in a 6-month controlled randomized study. The main emphasis of the treatment programme was to reduce daily sodium intake to less than 70 mmol. Mean sodium excretion decreased from 148 +/- 74 mmol 24 h-1 to 79 +/- 71 mmol 24 h-1 in the treatment group, but remained unchanged in the control group (173 +/- 68 mmol 24 h-1 vs. 186 +/- 62 mmol 24 h-1; P less than 0.01 for the difference in changes between the groups). Mean plasma ANF concentrations in the treatment group were 52.4 +/- 20.7 (median 50) pg ml-1 at baseline and 38.7 +/- 26.3 (median 42) pg ml-1 at 6 months, and the corresponding values in the control group were 55.5 +/- 20.5 (median 50) pg ml-1 and 46.1 +/- 32.4 (median 50) pg ml-1, respectively (P = NS for the difference in changes). The ANF concentration decreased from 70 +/- 14 pg ml-1 to 32 +/- 26 pg ml-1 in treated subjects with a high baseline plasma ANF concentration (greater than 50 pg ml-1), but increased from 37 +/- 11 pg ml-1 to 45 +/- 27 pg ml-1 in subjects with a low baseline plasma ANF concentration (less than or equal to 50 pg ml-1) (difference in changes P less than 0.001). Compared with treated subjects with low baseline plasma ANF levels and with controls, treated subjects with high baseline plasma ANF levels showed a decrease (P less than 0.05) in interventricular septal and left posterior wall thicknesses, in relative wall thickness, and in peripheral resistance. These results suggest that in mildly to moderately hypertensive subjects long-term sodium restriction decreases high plasma ANF concentrations concomitantly with regression of concentric left ventricular hypertrophy, probably as a result of changes in haemodynamics.

Adult

Hormone response of diabetic patients to exercise at cool and warm temperatures.

Both exercise and high ambient temperatures stimulate the secretion of counterregulatory hormones which can change glucose homeostasis. We studied whether in diabetic patients there are any differences in the hormonal response to exercise performed at cool or warm ambient temperatures. A study was performed on eight male insulin-dependent patients at rest and during exercise at +10 degrees C and +30 degrees C. Exercise consisted of three consecutive 15-min periods at 60% of maximal aerobic capacity. The concentrations of plasma lactate and counterregulatory hormones at rest were similar at warm and cool temperature, whereas prolactin concentration was higher (P less than 0.01) at +30 degrees C. Exercise resulted in an increase in noradrenaline, growth hormone and prolactin (P less than 0.01), prevented the diurnal decrease in cortisol, but had no effect on glucagon. Hormone responses to exercise were similar at +10 degrees C and at +30 degrees C, except for cortisol and noradrenaline which showed greater responses at warm than at cool temperatures. This may have been due to the higher relative work load at warm compared to cool temperatures as suggested by the higher heart rate and greater increase of lactate at +30 degrees C. These data indicate that within a range of ambient temperatures commonly occurring in sports, the response of counterregulatory hormones is largely independent of ambient temperature in insulin-dependent diabetic patients.

Adult

Serum lipids and lipoproteins in children, adolescents and young adults in 1980-1986.

A multicentre study on atherosclerosis precursors in young Finns aged three to 18 years was started in 1980 (3596 subjects) serum lipid concentrations (cholesterol, HDL (high density lipoprotein) cholesterol and triglycerides) were determined (n = 3554) and the apolipoproteins A-I and B measured (n = 1355). Two follow-up studies were carried out in 1983 (n = 2851) and 1986 (n = 2489), when HDL-subfractions (HDL-2-cholesterol and HDL-3-cholesterol) were also determined. Apolipoproteins A-I and B were measured again in 1986 (n = 1202). Serum total cholesterol concentration has fallen by about 1% annually during the 1980's from 5.07 mmol/l (1980) to 4.79 mmol/l (1986) in 9- to 18-year old children and adolescents. Mean values of serum triglycerides have slightly increased during the follow-up from 0.79 mmol/l to 0.84 mmol/l, respectively. In children and young adults (3-24 years) the mean cholesterol concentration was highest at the age of six and lowest during puberty. Concentrations of serum cholesterol, LDL (low density lipoprotein) cholesterol apoprotein B and triglycerides were higher in eastern than in western Finland in 1980 and 1983, but these differences were smaller in 1986, with the exception of serum triglycerides. Both in 1983 and in 1986 HDL-2-cholesterol was lower in the west than in the east, whereas HDL-3-cholesterol was higher in the former. The favourable changes in lipid levels should be reflected in future morbidity and mortality rates from coronary heart disease in Finland.

Adolescent

Regional differences in apolipoprotein E polymorphism in Finland.

Apolipoprotein E (apoE) polymorphism is a genetic determinant of plasma lipid levels and of coronary heart disease risk. We determined apoE phenotypes and plasma lipid levels in 1564 subjects aged three to 18 years, living in five geographical areas of Finland in 1980. ApoE phenotyping was performed directly from plasma by isoelectric focusing and immunoblotting. The serum concentrations of total cholesterol, low density lipoprotein cholesterol and apolipoprotein B varied with apoE phenotype, and there were increases in all three variables (all P less than 0.001) of the order of E2/2 less than E3/2 less than E4/2 less than E3/3 less than E4/3 less than E4/4. These differences were present in all five areas. The mean levels of high density lipoprotein cholesterol, apolipoprotein A-I and triglyceride in the subjects did not differ between the apoE phenotypes or between their areas of residence. The apoE phenotype dependency of serum total and LDL cholesterol remained significant in all five areas during the six year follow-up from 1980 to 1986, when the mean level of serum total cholesterol fell by 5.8% in east (P less than 0.05) and by 4.4% in west Finland (P less than 0.05); the fall was steeper (P less than 0.01) in the east than the west. In all subjects, particularly those in west Finland, the size of the falls of serum total and LDL cholesterol concentrations depended on the apoE phenotype in the order of E3/2 less than E3/3 less than E4/3, but this effect was not seen in the east.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Serum insulin and other cardiovascular risk indicators in children, adolescents and young adults.

We wanted to determine the levels of fasting serum insulin during growth, the tracking of serum insulin, and the correlation of serum insulin with other coronary heart disease risk indicators in children and young adults. In 1986 2433 subjects, aged nine to 24 were studied, and insulin data were available from the same population in 1980 and 1983. Serum insulin levels showed a peak during puberty in both sexes and the decline in insulin continued after the age of 21. Tracking of serum insulin was only moderate, especially in females and young boys. Serum insulin correlated positively with body mass index, concentrations of serum triglycerides, and blood pressure, and inversely with the concentration of high density lipoprotein cholesterol. High triglycerides, high systolic blood pressure, and low level of high density lipoprotein cholesterol clustered among subjects within the highest insulin quartile. Our results suggest that the insulin resistance phenomenon, caused mainly by obesity and leading to unfavourable levels of other coronary heart disease risk indicators, is already developing in children and young adults. This suggests that preventing obesity in early life is important.

Adolescent

Association of apolipoprotein E and B polymorphisms with serum lipids.

Genetic polymorphism of apolipoprotein E (apoE) and the Xbal restriction-fragment-length polymorphisms (RFLP) of the gene for apolipoprotein B (apoB) have both been shown to be associated with plasma lipid concentration. We studied the combined effect of these gene polymorphisms on serum cholesterol concentrations in 300 subjects aged nine to 18 years. In three way ANOVA, there was a statistically significant interaction between the effects of apoE phenotype and gender on serum cholesterol (P = 0.009). Therefore, males and females were analysed separately by two way ANOVA: there was no interaction between the effects of apoE phenotype and apoB Xbal polymorphism in either gender. In females, there were independent effects of both the apoE phenotype (P = 0.020) and the apoB Xbal genotype (P = 0.037) on serum cholesterol, but in males these effects were not statistically significant. These data suggest that variations at the apolipoprotein B and E gene locus play a role in the determination of serum cholesterol concentration in young female Finns.

Adolescent

Long-term nopharmacological treatment for mild to moderate hypertension.

Ninety-one middle-aged men and women with untreated mild hypertension were allocated to a nopharmacological treatment group or to a control group. Members of the treatment group were instructed to reduce daily sodium intake to less than 70 mmol, to reduce the intake of saturated fat, to lose weight if necessary and to perform regular physical exercise and relaxation training. Adherence to and effects of the programme on blood pressure and serum lipids were monitored for 12 months. In the treatment group, daily sodium excretion decreased to and remained at 50% of its original level (P less than 0.001), and there was a significant reduction in saturated fat intake. The average weight reduction was modest. Adherence to physical exercise and relaxation training regimens was poor. The net decreases (difference in changes between treatment and control group) in blood pressure were greatest during the first 3 months: in men the decrease in systolic blood pressure was 11.3 mmHg (P less than 0.001) and in diastolic blood pressure 8.3 mmHg (P less than 0.001); in women the decrease in systolic blood pressure was 10.8 mmHg (P less than 0.01) and in diastolic blood pressure 6.4 mmHg (P less than 0.01). However, this decrease diminished during the last 3 months to approximately one half owing to blood pressure reduction in controls. Low density lipoprotein cholesterol levels decreased significantly in treated men and women.

Adult

Apolipoprotein E phenotypes in Finnish youths: a cross-sectional and 6-year follow-up study.

Apolipoprotein E (apoE) polymorphism is a genetic determinant of plasma lipid levels and of coronary heart disease (CHD) risk. We determined the apoE phenotypes and plasma lipid levels in 1577 youths aged 3 to 18 years in 1980. The subjects were randomly selected from five areas of Finland. ApoE phenotyping was performed directly from plasma by isoelectric focusing and immunoblotting. The apoE allele frequencies in the population sample were epsilon 2 = 0.039, epsilon 3 = 0.767, and epsilon 4 = 0.194. There were no differences in the apoE phenotype distribution between East and West Finland or between sexes. The concentrations of serum total cholesterol, low density lipoprotein cholesterol, and apolipoprotein B increased with apoE phenotype in the order of E2/2, E3/2, E4/2, E3/3, E4/3, and E4/4. This increase was already seen in 3-year-old children; it was observed in both sexes, but was clearer in males than in females. The mean levels of high density lipoprotein (HDL) cholesterol, apolipoprotein A-I, triglyceride, Lp[a] lipoprotein, and the activity of lecithin:cholesterol acyltransferase did not differ between the apoE phenotypes. The observed differences in serum cholesterol remained fairly stable during the 6-year follow-up from 1980 to 1986, while the mean serum cholesterol concentration in the whole study population decreased by 6.3%. This study confirms the reported higher frequency of the epsilon 4 allele in Finns as compared to most other populations; this may contribute to the high rates of CHD in Finland as compared to most other populations. The results do not, however, explain the higher rate of CHD in East Finland in comparison to the western part of the country.

Adolescent

Lecithin: cholesterol acyltransferase activity in children and young adults.

The association between serum lecithin: cholesterol acyltransferase (LCAT) activity and demographic and environmental factors, and the correlation of LCAT activity with serum lipids and lipoproteins were studied in a representative series of 1071 9-24-year-old subjects from East and West Finland. LCAT activity was determined by a method involving the use of exogenous substrate. Males had higher LCAT activity than females and subjects from East Finland had significantly higher activity than those from West Finland. LCAT activity tended to be lowest shortly after puberty. Women using oral contraceptives had significantly lower LCAT activity than women not using them. Serum LCAT activity was not associated with body mass index, physical activity index or smoking. Serum LCAT activity correlated positively with most serum lipid and lipoprotein variables. The highest correlation coefficients were found between LCAT activity and total cholesterol. LCAT activity correlated positively with the change in serum total cholesterol which had occurred during the preceding 3 and 6 years in men. Our results suggest that sex hormonal factors are associated with serum LCAT activity. The results are also in accordance with the idea that activity of LCAT increases in response to enhanced demands for cholesterol esterification in plasma.

Adolescent

Serum lipids, lipoproteins, and apolipoproteins and the excessive occurrence of coronary heart disease in non-insulin-dependent diabetic patients.

Serum lipids, lipoproteins, and major apolipoproteins and their association with previous myocardial infarction were studied in patients with non-insulin-dependent diabetes mellitus (NIDDM) and nondiabetic subjects in East and West Finland in 1982-1984. NIDDM patients had higher age-adjusted serum triglyceride and apolipoprotein B levels and a higher apolipoprotein B/apolipoprotein A-I ratio, lower serum high density lipoprotein (HDL) cholesterol and apolipoprotein A-1 levels, and a lower HDL cholesterol/apolipoprotein A-1 ratio than nondiabetic subjects. With a few exceptions, these differences persisted after adjustment for body mass index, alcohol intake, physical activity, smoking, and hypertension, which suggests that the atherogenic serum lipoprotein pattern in NIDDM is an inherent feature of the disease. In general, the association of serum lipids, lipoproteins, and apolipoproteins with myocardial infarction was similar in nondiabetic subjects and NIDDM patients, although it was somewhat stronger in the diabetic subjects. A low serum HDL cholesterol/apolipoprotein A-1 ratio, which was closely linked to high serum triglyceride level, seemed to be more consistently related to myocardial infarction in NIDDM patients than in nondiabetic subjects. Serum lipids, lipoproteins, and apolipoproteins, either separately or in various combinations, could only to a small extent explain the higher prevalence of myocardial infarction in diabetic subjects compared with nondiabetic subjects when tested in multivariate analysis with other cardiovascular risk factors as background variables. The association between serum lipoproteins and myocardial infarction was largely similar in East and West Finland, two areas that differ markedly with respect to the occurrence of coronary heart disease.

Apolipoproteins

Factors associated with fasting and postglucagon plasma C-peptide levels in middle-aged insulin-treated diabetic patients.

We studied fasting and postglucagon plasma C-peptide levels and factors associated with them in two representative studies of middle-aged insulin-treated diabetic patients whose diabetes had been diagnosed after the age of 30 yr. Altogether, 75 men and 79 women from East Finland and 83 men and 62 women from West Finland aged 45-64 yr were studied. Of these patients, 44.4% had undetectable fasting and 38.5% undetectable postglucagon C-peptide concentrations. The phi-coefficient expressing the concordance of fasting and postglucagon C-peptide concentrations in the classification of diabetic patients into nonresponders and responders was .75 in men and .91 in women. In multiple stepwise regression analyses, body mass index (BMI) and the period between diabetes diagnosis and the initiation of insulin treatment were positively and duration of diabetes inversely associated with fasting and postglucagon C-peptide levels in both sexes. We concluded that 1) insulin deficiency is not uncommon in middle-aged insulin-treated diabetic patients whose diabetes has been diagnosed after the age of 30 yr; 2) fasting C-peptide levels contain basically the same information as postglucagon C-peptide levels; and 3) a low BMI, a need for insulin treatment soon after the diagnosis of diabetes, and a long duration of diabetes are predictive of insulin deficiency.

C-Peptide