Trends in blood pressure over 10 years in adolescents: analyses of cross sectional surveys in the Northern Ireland Young Hearts project
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《英国医生杂志》
1 Department of Child Health, Queens University of Belfast, Institute of Clinical Science, Royal Victoria Hospital, Belfast BT12 6JB, 2 Department of Epidemiology and Public Health, Queens University of Belfast, 3 Department of Applied Medical Sciences and Sports Studies, University of Ulster, Newtownabbey BT37 0QB, 4 Northern Ireland Centre for Diet and Health, University of Ulster, Coleraine BT52 1SA, 5 Department of Social Medicine, University of Bristol, Bristol BS8 2PR
Correspondence to: Dr David Watkins, Stepping Hill Hospital, Stockport SK2 7JE david.watkins@stockport-tr.nwest.nhs.uk
Abstract
Raised blood pressure is a major risk factor for cardiovascular disease.1 It tracks relatively well from youth to adulthood, making blood pressure in youth a useful predictor of essential hypertension in adulthood.2 3 Patterns of risk factors in populations, such as raised blood pressure, are not static over time, and predate subsequent changes in patterns of cardiovascular disease.4 Evidence from the United States and worldwide shows that the mean blood pressure of adults has decreased over the past two decades.5 6 Fewer data are available on trends in youth; findings from the United States have been inconsistent, whereas in the United Kingdom, secular decreases in blood pressure have been noted in successive cohorts of university students.7-9
Trends in blood pressure in adolescents are a marker of the future population burden of cardiovascular disease and may be of particular relevance in areas with high disease rates.10 We examined trends in blood pressure in representative samples of adolescents in Northern Ireland, a region with a consistently high prevalence of cardiovascular disease.11
Participants and methods
The response rate for the second study was lower than that for the first (65.3% compared with 79.3%). Reasons for non-participation were similarly distributed between both studies: 40% of respondents objected to a blood test, 26% were not interested in taking part, 16% were unwilling to miss schoolwork, and 4% were unwilling to undergo a fitness test. On the basis of limited self-reported anthropometric data from non-participants, body mass index (weight (kg)/(height (m)2)) was 0.9 lower in non-participants than in participants.
Although there was disagreement between the observers for some blood pressure readings, as evidenced by the large standard deviations of the differences between the two observers (mean (SD) difference: systolic 0.10 (10.40) mm Hg; diastolic 0.24 (10.76) mm Hg), there was no evidence of systematic variation between them, with similar mean systolic and diastolic blood pressures being recorded by both. In regression models with systolic and diastolic blood pressure as the dependent variables, and the effects of participant, machine, and observer as explanatory variables, there was no evidence that observer effect had influenced blood pressure measurement (data not shown).
The analyses in tables 2 and 3 are based on participants with complete data, representing 99% of the original cohorts. We found consistent differences in mean blood pressure between both sexes, males tending to have higher systolic and lower diastolic blood pressure than age matched females (table 1). These findings remained largely unchanged between the two studies. Correlations between systolic and diastolic blood pressure were of a similar order (0.5 to 0.65) in both studies and for all four groups.
Table 2 Characteristics of participants of Young Hearts studies, 1990 and 2000. Values are means (standard deviations) unless stated otherwise
Table 3 Decreases in mean blood pressure over 10 years in participants of Young Hearts studies, 1990 and 2000. Values are means (95% confidence intervals)
Table 1 Mean (SD) systolic and diastolic blood pressures in participants from Young Hearts studies, 1990 and 2000
Table 2 shows the summary statistics for potential confounding or mediating variables. Mean height increased substantially in the four groups (by 1.9 cm to 3.0 cm, P < 0.001 for each group) as did mean weight (by 1.5 kg to 4.2 kg, P < 0.001 to P = 0.04), with the largest increases among 12 year olds. Mean body mass index only increased significantly in 12 year old females. Mean birth weight changed little between the first and second study (3372 g versus 3408 g, respectively; P = 0.10). The proportion of females of both ages who smoked regularly, increased. Mean maximal aerobic fitness and mean habitual physical activity showed more favourable trends in males. The proportion of participants who were breast fed as infants increased in all four groups over the 10 year period, as did the proportion from a non-manual background (59.2% versus 72.8%; P < 0.001).
Table 3 shows the change in mean systolic and diastolic blood pressure for the four groups between the first and second study, unadjusted and adjusted for age, height, body mass index, smoking status, physical activity, and stratification of school. Substantial decreases were found consistently across all four groups for both systolic blood pressure (mean unadjusted decrease 7.7 mm Hg to 10.0 mm Hg) and diastolic blood pressure (8.8 mm Hg to 11.0 mm Hg); this represents an annual decline of 0.73 mm Hg to 1.01 mm Hg and 0.89 mm Hg to 1.09 mm Hg, respectively. Additional modelling, controlling for age, height, body mass index, smoking status, physical activity, stratification of school, breast feeding, and fitness, and then additionally controlling for birth weight, social class, and pubertal status, had negligible effects on the results presented in table 3 (data not shown).
Discussion
Stamler J, Stamler R, Neaton JD. Blood pressure, systolic and diastolic, and cardiovascular risks. US population data. Arch Intern Med 1993;153: 598-615.
Bao W, Threefoot SA, Srinivasan SR, Berenson GS. Essential hypertension predicted by tracking of elevated blood pressure from childhood to adulthood: the Bogalusa Heart Study. Am J Hypertens 1995;8: 657-65.
Lauer RM, Clarke WR. Childhood risk factors for high adult blood pressure: the muscatine study. Pediatrics 1989;84: 633-41.
Thom TJ. International mortality from heart disease: rates and trends. Int J Epidemiol 1989;18: S20-8.
Burt VL, Culter JA, Higgins M, Horan MJ, Labarthe D, Whelton P, et al. Trends in the prevalence, awareness, treatment, and control of hypertension in the adult US population. Data from the health examination surveys, 1960 to 1991. Hypertension 1995;26: 60-9.
Kuulasmaa K, Tunstall-Pedoe H, Dobson A, Fortmann S, Sans S, Tolonen H, et al. Estimation of contribution of changes in classic risk factors to trends in coronary-event rates across the WHO MONICA Project populations. Lancet 2000;355: 675-87.
Gidding SS, Bao W, Srinivasan SR, Berenson GS. Effects of secular trends in obesity on coronary risk factors in children: the Bogalusa Heart Study. J Pediatr 1995;127: 868-74.
Luepker RV, Jacobs DR, Prineas RJ, Sinaiko AR. Secular trends of blood pressure and body size in a multi-ethnic adolescent population: 1986 to 1996. J Pediatr 1999;134: 668-74.
McCarron P, Okasha M, McEwen J, Davey Smith G. Changes in blood pressure among students attending Glasgow University between 1948 and 1968: analyses of cross sectional surveys. BMJ 2001;322: 885-9.
McCarron P, Davey Smith G, Okasha M, McEwen J. Blood pressure in young adulthood and mortality from cardiovascular disease. Lancet 2000;355: 1430-1.
Uemura K, Pisa Z. Trends in cardiovascular disease mortality in industrialized countries since 1950. World Health Stat Q 1988;41: 155-78.
Boreham C, Savage JM, Primrose D, Cran G, Strain J. Coronary risk factors in school-children. Arch Dis Child 1993;68: 182-6.
Wright BM, Dore CF. A random-zero sphygmomanometer. Lancet 1970; 337-8.
De Swiet M, Dillon MJ, Littler W, O'Brien E, Padfield PL, Petrie JC. Measurement of blood pressure in children. Recommendations of a working party of the British Hypertension Society. BMJ 1989;299: 497.
Tanner JM. Growth at adolescence. Oxford: Blackwell, 1962.
Boreham CA, Paliczka VJ, Nichols AK. A comparison of the PWC170 and 20-MST tests of aerobic fitness in adolescent schoolchildren. J Sports Med Phys Fitness 1990;30: 19-23.
Walton KA, Murray LJ, Gallagher AM, Cran GW, Savage MJ, Boreham C. Parental recall of birthweight: a good proxy for recorded birthweight? Eur J Epidemiol 2000;16: 793-6.
Roberts J. Cardiovascular conditions of children aged 6-11 years and youths 12-17 years. United States, 1963-1965 and 1966-1970. National Center for Health Statistics, Vital Health Stat Series11 (166), 1978.
Department of Health. Health Survey for England: trend data for children 1995-1998, children's reference tables '98. London: Department of Health, 2002.
McCarron P, Davey Smith G, Okasha M. Secular changes in blood pressure in childhood, adolescence and young adulthood: systematic review of trends from 1948 to 1998. J Hum Hypertens. 2002;16: 677-89.
Kotchen JM, McKean HE, Neill M, Kotchen TA. Blood pressure trends associated with changes in height and weight from early adolescence to young adulthood. J Clin Epidemiol 1989;42: 735-41.
Berenson GS, Wattigney WA, Webber LS. Epidemiology of hypertension from childhood to young adulthood in black, white, and Hispanic population samples. Public Health Rep 1996;111(suppl 2): 3-6.
Huxley RR, Shiell AW, Law CM. The role of size at birth and postnatal catch-up growth in determining systolic blood pressure: a systematic review of the literature. J Hypertens 2000;18: 815-31.
Huxley R, Neil A, Collins R. Unravelling the fetal origins hypothesis: is there really an inverse association between birthweight and subsequent blood pressure? Lancet 2002;360: 659-65.
Ebrahim S, Davey Smith G. Lowering blood pressure: a systematic review of sustained effects of non-pharmacological interventions. J Public Health Med 1998;20: 441-8.
Geleijnse JM, Hofman A, Witteman JC, Hazebroek AA, Valkenburg HA, Grobbee DE. Long-term effects of neonatal sodium restriction on blood pressure. Hypertension 1997;29: 913-7.(David Watkins, consultant)
Correspondence to: Dr David Watkins, Stepping Hill Hospital, Stockport SK2 7JE david.watkins@stockport-tr.nwest.nhs.uk
Abstract
Raised blood pressure is a major risk factor for cardiovascular disease.1 It tracks relatively well from youth to adulthood, making blood pressure in youth a useful predictor of essential hypertension in adulthood.2 3 Patterns of risk factors in populations, such as raised blood pressure, are not static over time, and predate subsequent changes in patterns of cardiovascular disease.4 Evidence from the United States and worldwide shows that the mean blood pressure of adults has decreased over the past two decades.5 6 Fewer data are available on trends in youth; findings from the United States have been inconsistent, whereas in the United Kingdom, secular decreases in blood pressure have been noted in successive cohorts of university students.7-9
Trends in blood pressure in adolescents are a marker of the future population burden of cardiovascular disease and may be of particular relevance in areas with high disease rates.10 We examined trends in blood pressure in representative samples of adolescents in Northern Ireland, a region with a consistently high prevalence of cardiovascular disease.11
Participants and methods
The response rate for the second study was lower than that for the first (65.3% compared with 79.3%). Reasons for non-participation were similarly distributed between both studies: 40% of respondents objected to a blood test, 26% were not interested in taking part, 16% were unwilling to miss schoolwork, and 4% were unwilling to undergo a fitness test. On the basis of limited self-reported anthropometric data from non-participants, body mass index (weight (kg)/(height (m)2)) was 0.9 lower in non-participants than in participants.
Although there was disagreement between the observers for some blood pressure readings, as evidenced by the large standard deviations of the differences between the two observers (mean (SD) difference: systolic 0.10 (10.40) mm Hg; diastolic 0.24 (10.76) mm Hg), there was no evidence of systematic variation between them, with similar mean systolic and diastolic blood pressures being recorded by both. In regression models with systolic and diastolic blood pressure as the dependent variables, and the effects of participant, machine, and observer as explanatory variables, there was no evidence that observer effect had influenced blood pressure measurement (data not shown).
The analyses in tables 2 and 3 are based on participants with complete data, representing 99% of the original cohorts. We found consistent differences in mean blood pressure between both sexes, males tending to have higher systolic and lower diastolic blood pressure than age matched females (table 1). These findings remained largely unchanged between the two studies. Correlations between systolic and diastolic blood pressure were of a similar order (0.5 to 0.65) in both studies and for all four groups.
Table 2 Characteristics of participants of Young Hearts studies, 1990 and 2000. Values are means (standard deviations) unless stated otherwise
Table 3 Decreases in mean blood pressure over 10 years in participants of Young Hearts studies, 1990 and 2000. Values are means (95% confidence intervals)
Table 1 Mean (SD) systolic and diastolic blood pressures in participants from Young Hearts studies, 1990 and 2000
Table 2 shows the summary statistics for potential confounding or mediating variables. Mean height increased substantially in the four groups (by 1.9 cm to 3.0 cm, P < 0.001 for each group) as did mean weight (by 1.5 kg to 4.2 kg, P < 0.001 to P = 0.04), with the largest increases among 12 year olds. Mean body mass index only increased significantly in 12 year old females. Mean birth weight changed little between the first and second study (3372 g versus 3408 g, respectively; P = 0.10). The proportion of females of both ages who smoked regularly, increased. Mean maximal aerobic fitness and mean habitual physical activity showed more favourable trends in males. The proportion of participants who were breast fed as infants increased in all four groups over the 10 year period, as did the proportion from a non-manual background (59.2% versus 72.8%; P < 0.001).
Table 3 shows the change in mean systolic and diastolic blood pressure for the four groups between the first and second study, unadjusted and adjusted for age, height, body mass index, smoking status, physical activity, and stratification of school. Substantial decreases were found consistently across all four groups for both systolic blood pressure (mean unadjusted decrease 7.7 mm Hg to 10.0 mm Hg) and diastolic blood pressure (8.8 mm Hg to 11.0 mm Hg); this represents an annual decline of 0.73 mm Hg to 1.01 mm Hg and 0.89 mm Hg to 1.09 mm Hg, respectively. Additional modelling, controlling for age, height, body mass index, smoking status, physical activity, stratification of school, breast feeding, and fitness, and then additionally controlling for birth weight, social class, and pubertal status, had negligible effects on the results presented in table 3 (data not shown).
Discussion
Stamler J, Stamler R, Neaton JD. Blood pressure, systolic and diastolic, and cardiovascular risks. US population data. Arch Intern Med 1993;153: 598-615.
Bao W, Threefoot SA, Srinivasan SR, Berenson GS. Essential hypertension predicted by tracking of elevated blood pressure from childhood to adulthood: the Bogalusa Heart Study. Am J Hypertens 1995;8: 657-65.
Lauer RM, Clarke WR. Childhood risk factors for high adult blood pressure: the muscatine study. Pediatrics 1989;84: 633-41.
Thom TJ. International mortality from heart disease: rates and trends. Int J Epidemiol 1989;18: S20-8.
Burt VL, Culter JA, Higgins M, Horan MJ, Labarthe D, Whelton P, et al. Trends in the prevalence, awareness, treatment, and control of hypertension in the adult US population. Data from the health examination surveys, 1960 to 1991. Hypertension 1995;26: 60-9.
Kuulasmaa K, Tunstall-Pedoe H, Dobson A, Fortmann S, Sans S, Tolonen H, et al. Estimation of contribution of changes in classic risk factors to trends in coronary-event rates across the WHO MONICA Project populations. Lancet 2000;355: 675-87.
Gidding SS, Bao W, Srinivasan SR, Berenson GS. Effects of secular trends in obesity on coronary risk factors in children: the Bogalusa Heart Study. J Pediatr 1995;127: 868-74.
Luepker RV, Jacobs DR, Prineas RJ, Sinaiko AR. Secular trends of blood pressure and body size in a multi-ethnic adolescent population: 1986 to 1996. J Pediatr 1999;134: 668-74.
McCarron P, Okasha M, McEwen J, Davey Smith G. Changes in blood pressure among students attending Glasgow University between 1948 and 1968: analyses of cross sectional surveys. BMJ 2001;322: 885-9.
McCarron P, Davey Smith G, Okasha M, McEwen J. Blood pressure in young adulthood and mortality from cardiovascular disease. Lancet 2000;355: 1430-1.
Uemura K, Pisa Z. Trends in cardiovascular disease mortality in industrialized countries since 1950. World Health Stat Q 1988;41: 155-78.
Boreham C, Savage JM, Primrose D, Cran G, Strain J. Coronary risk factors in school-children. Arch Dis Child 1993;68: 182-6.
Wright BM, Dore CF. A random-zero sphygmomanometer. Lancet 1970; 337-8.
De Swiet M, Dillon MJ, Littler W, O'Brien E, Padfield PL, Petrie JC. Measurement of blood pressure in children. Recommendations of a working party of the British Hypertension Society. BMJ 1989;299: 497.
Tanner JM. Growth at adolescence. Oxford: Blackwell, 1962.
Boreham CA, Paliczka VJ, Nichols AK. A comparison of the PWC170 and 20-MST tests of aerobic fitness in adolescent schoolchildren. J Sports Med Phys Fitness 1990;30: 19-23.
Walton KA, Murray LJ, Gallagher AM, Cran GW, Savage MJ, Boreham C. Parental recall of birthweight: a good proxy for recorded birthweight? Eur J Epidemiol 2000;16: 793-6.
Roberts J. Cardiovascular conditions of children aged 6-11 years and youths 12-17 years. United States, 1963-1965 and 1966-1970. National Center for Health Statistics, Vital Health Stat Series11 (166), 1978.
Department of Health. Health Survey for England: trend data for children 1995-1998, children's reference tables '98. London: Department of Health, 2002.
McCarron P, Davey Smith G, Okasha M. Secular changes in blood pressure in childhood, adolescence and young adulthood: systematic review of trends from 1948 to 1998. J Hum Hypertens. 2002;16: 677-89.
Kotchen JM, McKean HE, Neill M, Kotchen TA. Blood pressure trends associated with changes in height and weight from early adolescence to young adulthood. J Clin Epidemiol 1989;42: 735-41.
Berenson GS, Wattigney WA, Webber LS. Epidemiology of hypertension from childhood to young adulthood in black, white, and Hispanic population samples. Public Health Rep 1996;111(suppl 2): 3-6.
Huxley RR, Shiell AW, Law CM. The role of size at birth and postnatal catch-up growth in determining systolic blood pressure: a systematic review of the literature. J Hypertens 2000;18: 815-31.
Huxley R, Neil A, Collins R. Unravelling the fetal origins hypothesis: is there really an inverse association between birthweight and subsequent blood pressure? Lancet 2002;360: 659-65.
Ebrahim S, Davey Smith G. Lowering blood pressure: a systematic review of sustained effects of non-pharmacological interventions. J Public Health Med 1998;20: 441-8.
Geleijnse JM, Hofman A, Witteman JC, Hazebroek AA, Valkenburg HA, Grobbee DE. Long-term effects of neonatal sodium restriction on blood pressure. Hypertension 1997;29: 913-7.(David Watkins, consultant)