어린이 비만, 다른 심혈관계 위험 요인, 그리고 조숙 사망

1945년~1985년에 태어난 당뇨병이 없는 American Indian 어린이  4857명의 cohort  연구결과가 NEJM 최신호에 발표되었습니다.

체질량지수(BMI), 당 불내성(glucose tolerance), 혈압, 콜레스테롤 수치에 따른 내부적인 원인에 의한 조숙사망을 예측하였습니다.

그 결과 체질량지수(BMI), 당 불내성(glucose tolerance), 혈압과 내부적인 원인에 의한 조숙사망률은 아주 강한 연관관계가 있다는 사실이 밝혀졌습니다.

반면 어린이의 고지혈증(hypercholesterolemia)은 내부적인 원인에 의한 조숙사망률과 상관관계가 없는 것으로 밝혀졌습니다.

논문의 전문은 아래 내용과 첨부파일을 참조하시기 바랍니다.

한편 호주 멜버른 모나시 대학의 폴 오브라이언 박사팀이 최근 미국의사협회저널에 실은 보고서에서 “비만인 경우 위밴드수술을 받는 것이 체중 감량에 더욱 크고 지속적인 효과를 나타내는 것으로 나타났다”고 주장했다는 뉴스를 맨 아래에 첨부합니다.

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ABSTRACT

Background The effect of childhood risk factors for cardiovascular disease on adult mortality is poorly understood.

Methods In a cohort of 4857 American Indian children without diabetes (mean age, 11.3 years; 12,659 examinations) who were born between 1945 and 1984, we assessed whether body-mass index (BMI), glucose tolerance, and blood pressure and cholesterol levels predicted premature death. Risk factors were standardized according to sex and age. Proportional-hazards models were used to assess whether each risk factor was associated with time to death occurring before 55 years of age. Models were adjusted for baseline age, sex, birth cohort, and Pima or Tohono O’odham Indian heritage.

Results There were 166 deaths from endogenous causes (3.4% of the cohort) during a median follow-up period of 23.9 years. Rates of death from endogenous causes among children in the highest quartile of BMI were more than double those among children in the lowest BMI quartile (incidence-rate ratio, 2.30; 95% confidence interval [CI], 1.46 to 3.62). Rates of death from endogenous causes among children in the highest quartile of glucose intolerance were 73% higher than those among children in the lowest quartile (incidence-rate ratio, 1.73; 95% CI, 1.09 to 2.74). No significant associations were seen between rates of death from endogenous or external causes and childhood cholesterol levels or systolic or diastolic blood-pressure levels on a continuous scale, although childhood hypertension was significantly associated with premature death from endogenous causes (incidence-rate ratio, 1.57; 95% CI, 1.10 to 2.24).

Conclusions Obesity, glucose intolerance, and hypertension in childhood were strongly associated with increased rates of premature death from endogenous causes in this population. In contrast, childhood hypercholesterolemia was not a major predictor of premature death from endogenous causes.

Despite recent increases in life expectancy, the rising global prevalence of obesity may reverse this trend.¹ The rising rates and increasingly early onset of other chronic diseases such as type 2 diabetes may also affect mortality rates.²

Cardiovascular risk factors are common in children.^3,4 Although early-onset diabetes has been shown to raise mortality rates,² and the relation between cardiovascular risk factors during adulthood and early death is well defined,^5,6,7 little is known about the way in which cardiovascular risk factors that are present during childhood affect life span. Defining such relationships may help predict the long-term human and economic costs of cardiovascular risk factors in childhood and might justify interventions that are intended to improve health and reduce the rates of premature death.

In this study, we assessed the extent to which obesity, glucose intolerance, hypertension, and hypercholesterolemia in children without diabetes predicted premature death (defined as death before 55 years of age) in American Indians from Arizona.

Methods

Study Population

We invited residents in a well-defined geographic area of the Gila River Indian Community in Arizona, most of whom were Pima or Tohono O’odham Indians,^8,9 to participate in a longitudinal study of diabetes and related disorders. Pima or Tohono O’odham Indian heritage was defined by the heritage of each of the child’s parents, grandparents, and great-grandparents, as reported by the parents of the participating children. Included in the study were 4857 children and adolescents (5 to <20 years of age) who had at least 4/8 Pima or Tohono O’odham Indian heritage, did not have diabetes, and underwent one or more research examinations between February 1966 and December 2003. Participants were born between 1945 and 1984 and resided on the reservation during the study. Participants who were 18 years of age or older gave written informed consent; those younger than 18 years of age gave written assent and a parent or guardian gave written informed consent. The institutional review board of the National Institute of Diabetes and Digestive and Kidney Diseases approved the study.

Study Examinations

We assessed the extent to which childhood body-mass index (BMI), 2-hour plasma glucose level during a 75-g oral glucose-tolerance test, and blood pressure and total cholesterol levels predicted premature death. The baseline examination was the first examination at which all these variables were measured. The analyses included data from the date of the baseline examination until the person’s death, the person’s 55th birthday, or the end of 2003, whichever came first. Vital status was ascertained as of December 31, 2003. Death records for community residents were maintained throughout the study period. Copies of death certificates were obtained. The underlying cause of death was classified as endogenous or external. We defined deaths due to endogenous causes as those in which the proximate cause was disease or self-inflicted injury, such as acute alcohol intoxication or drug use, and deaths due to external causes as those that resulted from such causes as accidents or homicide. These definitions are consistent with those used in previous mortality studies undertaken in this cohort.¹⁰ The cause of death was determined from a review of available clinical autopsy records and death certificates. (For a list of the specific causes of death and the corresponding International Classification of Diseases, 9th Revision [ICD-9] codes, see the Supplementary Appendix, available with the full text of this article at NEJM.org.)

All participants underwent a 75-g oral glucose-tolerance test; results were interpreted according to World Health Organization diagnostic criteria.¹¹ We considered diabetes to be present if the fasting plasma glucose concentration was more than 7.0 mmol per liter (126 mg per deciliter), if the 2-hour plasma glucose concentration was 11.1 mmol per liter (200 mg per deciliter) or more, or if a previous clinical diagnosis was documented. Blood pressure was measured and standard anthropometric data were obtained while participants were wearing lightweight clothing and no shoes; the data were collected by trained study personnel.^8,9,12 No measures of puberty were available. Blood assays were performed as described previously.^8,9,12 Alcohol dependence in adulthood (for which data were available from 2672 of the participants) was estimated with the use of the CAGE questionnaire.¹³

Statistical Analysis

Analyses were performed with the use of SAS software, version 9.1 (SAS Institute). The characteristics of the participants are presented as arithmetic means (±SD) or, in the case of characteristics with skewed distributions, as medians and ranges. The z scores, which were standardized within sex and 1-year age strata, were computed for use in regression analyses. Age-standardized and sex-standardized incidence was calculated by the direct method with the use of the total study population as the reference group. Incidence-rate ratios were calculated from the incidence data with the use of Poisson regression controlled for age, sex, and Pima or Tohono O’odham Indian heritage. For incidence analyses, follow-up was truncated at 55 years of age, since there were few person-years beyond that point. Cox proportional-hazards models were used to test for associations between the baseline childhood risk factors and time to death, with adjustment for baseline age, sex, Pima or Tohono O’odham Indian heritage, and birth year, since birth year was correlated with many variables of interest (e.g., r=0.36 for the correlation between BMI and birth year). We tested the validity of the proportionality assumption for each variable by including a time-dependent interaction term in the baseline models.¹⁴ When this assumption was violated, stratified proportional-hazards models were fitted and a summarized incidence-rate ratio was calculated across strata; no material differences in death rates were observed across sex and baseline-age strata (data not shown).

Results

Premature Death among Study Participants

Table 1 shows the baseline characteristics of the participants. During the follow-up period, 559 of the 4857 participants (11.5%) died before they reached 55 years of age. A total of 166 deaths were from endogenous causes: 59 were attributed to alcoholic liver disease, 22 to cardiovascular disease, 21 to infections, 12 to cancer, 10 to diabetes or diabetic nephropathy, 9 to acute alcoholic poisoning or drug overdose, and 33 to other causes (see the Supplementary Appendix for a list of ICD-9 codes). Table 2 shows the rates of premature death by 10-year age strata.

View this table: [in this window] [in a new window]   Table 1. Baseline Characteristics of the Participants and Prevalence of Death before 55 Years of Age.

 

View this table: [in this window] [in a new window]   Table 2. Premature Death among Study Participants, According to Age at Study Entry.

 
Childhood Obesity and Premature Death

BMI was positively associated with the risk of premature death from endogenous causes (incidence-rate ratio per 1 unit of BMI z score, 1.40; 95% confidence interval [CI], 1.20 to 1.63). BMI was positively, but not significantly, associated with death from external causes (incidence-rate ratio per 1 SD of standardized BMI, 1.19; 95% CI, 1.00 to 1.42).

Children in the highest quartile of age-standardized and sex-standardized BMI had significantly higher rates of death than did children in the lowest quartile (Figure 1 and Table 3). The rates of death from endogenous causes among children in the highest quartile of BMI were more than double those among children in the lowest quartile (incidence-rate ratio, 2.30; 95% CI, 1.46 to 3.62) (Table 3). This finding could not be explained just by the presence of extremely obese children in the highest quartile, however, since none of the 51 extremely obese children (BMI z score >3) died during the follow-up period, possibly because these participants were younger and from more recent birth cohorts (median follow-up, 21.4 years) than participants who were less obese. The association between BMI and premature death from endogenous causes was attenuated but remained significant after adjustment for baseline glucose level, cholesterol level, and blood pressure (incidence-rate ratio for the highest BMI quartile vs. the lowest quartile, 1.41; 95% CI, 1.19 to 1.67) (Table 3).

View larger version (36K): [in this window] [in a new window]   Figure 1. Kaplan–Meier Curves for Premature Death. The graphs show the rates of premature death from all causes, external causes, and endogenous causes according to quartiles of age-standardized and sex-standardized body-mass index at different baseline ages during childhood and adolescence. Plots were computed with the use of baseline data. Age at baseline for each age group was taken as the midpoint of the age range.

 

View this table: [in this window] [in a new window]   Table 3. Incidence-Rate Ratios for Premature Death, According to Quartile of Variables.

 
A total of 1394 of the children (28.7%) were obese, which was defined as a BMI in the 95th percentile or higher on the Centers for Disease Control and Prevention (CDC) growth charts.¹⁵ Among the obese children as compared with the nonobese children, the incidence-rate ratios were 1.31 (95% CI, 1.10 to 1.57) for premature death from all causes, 1.90 (95% CI, 1.37 to 2.65) for death from endogenous causes, and 1.14 (95% CI, 0.92 to 1.41) for death from external causes.

Childhood Glucose, Cholesterol, and Blood-Pressure Levels and Premature Death

The 2-hour plasma glucose level during a 75-g oral glucose-tolerance test, expressed in age-standardized and sex-standardized units, was not associated with premature death from either endogenous or external causes. However, children in the highest quartile of glucose level had a 73% higher risk of premature death from endogenous causes than children in the lowest quartile (Table 3). Adjustment for childhood BMI reduced the magnitude of the association (incidence-rate ratio, 1.24; 95% CI, 0.79 to 1.96).

In models of impaired glucose tolerance (i.e., 2-hour glucose level of 7.8 to 11.0 mmol per liter [140 to 199 mg per deciliter])¹⁸ as compared with normal glucose tolerance as the predictor variable, the incidence-rate ratios were 0.90 (95% CI, 0.63 to 1.30) for all-cause premature death, 0.81 (95% CI, 0.39 to 1.65) for death from endogenous causes, and 0.94 (95% CI, 0.62 to 1.43) for death from external causes. Children with impaired glucose tolerance accounted for 15% of the children in the highest quartile of plasma glucose levels and were all in the top decile of the standardized 2-hour glucose distribution.

No significant associations were observed between death rates and childhood cholesterol levels or blood pressure (Table 3). In models in which hypercholesterolemia, as defined by the American Heart Association cutoff point (total cholesterol level, 5.18 mmol per liter [200 mg per deciliter]), was used as the predictor variable,¹⁷ the incidence-rate ratios were 1.33 (95% CI, 0.95 to 1.88) for all-cause premature death, 1.70 (95% CI, 0.96 to 3.01) for death from endogenous causes, and 1.18 (95% CI, 0.77 to 1.80) for death from external causes.

With hypertension defined according to the criteria of the National High Blood Pressure Education Program¹⁶ in the case of children and as 140/90 mm Hg or higher in the case of participants 18 years of age or older, there was no significant association with rates of death from all causes (incidence-rate ratio, 1.15; 95% CI, 0.93 to 1.43) or from external causes (incidence-rate ratio, 0.98; 95% CI, 0.75 to 1.29). However, childhood hypertension was strongly associated with the rate of death from endogenous causes (incidence-rate ratio, 1.57; 95% CI, 1.10 to 2.24).

Potential Mediators of the Association between Obesity and Death

Most deaths occurred in study participants who were not known to have diabetes. Of the 559 participants in whom diabetes developed, 79 died: 40 from endogenous causes and 39 from external causes. Adjusting the BMI prediction models for incident diabetes did not significantly alter the risk estimates (incidence-rate ratio for the highest BMI quartile vs. the lowest quartile, 2.70; 95% CI, 1.70 to 4.31). In contrast, inclusion of diabetes in the 2-hour glucose model reduced the risk estimate for the highest quartile of 2-hour glucose levels, and the association between the highest and lowest quartiles was not significant (incidence-rate ratio, 1.10; 95% CI, 0.72 to 1.68). In Cox proportional-hazards models that included 2672 participants, there were no significant associations between childhood BMI and alcohol dependency in adulthood (incidence-rate ratio per unit of BMI z score, 1.01; 95% CI, 0.96 to 1.07).

Discussion

It is well known that obesity, glucose intolerance, hypertension, and hypercholesterolemia in adulthood increase mortality rates. We conducted the present study to determine whether the presence of these risk factors in childhood predicts premature death. The rate of death from endogenous causes in the highest quartile of childhood BMI was more than double that in the lowest quartile, and the rate in the highest quartile of childhood two-hour plasma glucose levels during a 75-g oral glucose-tolerance test was 73% higher than that in the lowest quartile. Although neither blood pressure nor cholesterol level in childhood, when included as a continuous variable, significantly predicted premature death, childhood hypertension increased the risk of premature death from endogenous causes by 57%.

The absence of an association between premature death and cholesterol levels may be due partly to the low proportion of deaths due to cardiovascular disease in this cohort (13.3%). Treatment for any of the predictor traits during childhood or during adulthood did not appear to explain the pattern of association (data not shown). No childhood risk factor that was examined significantly predicted rates of premature death from external causes.

Childhood obesity predicted premature death from endogenous, but not external, causes. The study was not powered to analyze effects on more specific categories of cause of death. Including only liver-related causes of death in the analysis reduced the magnitude of the association of premature death with childhood BMI and with the 2-hour glucose level, but the direction and pattern of associations were similar to those observed when all endogenous causes of death were included.

We considered whether the relationship between childhood BMI and premature death reflects associations with adiposity or some other component of body mass. Our study began before the availability of modern adiposity measures such as dual-energy x-ray absorptiometry. However, we previously reported relationships between BMI and adipose mass and between adipose mass and the cardiovascular risk factors in this population¹⁹; in that study, BMI and adiposity were strongly correlated (r>0.96), varying little with age and sex, and BMI and adipose mass were similarly correlated with the cardiovascular risk factors. Thus, the observations for childhood BMI reported here are likely to reflect a positive association between adiposity and rates of premature death.

In a study involving 508 U.S. adolescents (13 to 18 years of age) who were born between 1922 and 1935, overweight (>75th percentile of the sample distribution) was associated with increased rates of death due to coronary heart disease.²⁰ Two studies have assessed the relationship between body weight and mortality in European birth cohorts from the early 20th century.^21,22 In a study of 2299 Welsh children born between 1937 and 1939, there was no association between childhood BMI and death from cardiovascular causes.²¹ However, there was an association between childhood BMI and death from all causes; the lowest rate of death was seen in the next-to-lowest BMI quartile and the highest rate of death in the highest quartile, suggesting that, as in the case of adult Pima Indians,²³ a U-shaped relationship exists between obesity and mortality. In the second European study, involving 504 overweight children and adolescents admitted to hospitals in Stockholm between 1921 and 1947, weight gain between puberty and young adulthood was associated with cardiovascular disease, diabetes, and death from all causes.²² A limitation of these studies is that obesity was uncommon during the study period. For example, of the 2299 children in the Welsh study,²¹ only 92 (4.0%) had a BMI above the 90th percentile for the age-specific and sex-specific distributions of the 1990 British population, and British children in 1990 were leaner than their contemporary counterparts.²⁴

In the Arizona Pima Indians, unlike most other ethnic groups, childhood obesity has been common for decades.²⁵ It has been estimated that at the turn of the 21st century, approximately 15% of U.S. children between the ages of 6 and 19 years (11 million children) were overweight or obese,²⁶ a prevalence that is unlikely to decline in the near future²⁷ and that is triple the prevalence among children of the same age in the 1960s.^28,29 In the present study, 1394 children (28.7%) were obese (BMI, 95th percentile on the 2000 CDC growth charts). This prevalence is similar to that observed in contemporary Hispanic and African-American children.²⁷ Thus, although we studied a population with high rates of obesity and diabetes, our findings may reflect the future burden of premature death among contemporary children from other ethnic groups and may be more generalizable than the findings in previous studies.

In this study, we compared mortality rates with several clinical risk factors as variables. Adjusting the obesity models for the development of diabetes in adulthood did not significantly alter the risk estimates, whereas adjusting the glucose models for subsequent diabetes did attenuate the association between childhood glucose levels and premature death. Hence, dysregulated glucose metabolism in childhood may be a mediator of the effects of childhood obesity on mortality rates, but it does not appear to be the sole or dominant factor; however, the association between childhood glucose intolerance and premature death does appear to be mediated by the development of subsequent diabetes.

The pattern of the relationships between the risk factors and observed mortality supports the view that childhood obesity is an early metabolic derangement, whereas most of the other risk factors evolve later. In fact, the predictive power of a risk score for type 2 diabetes (including measures of obesity and insulin, blood-pressure, glucose, and lipid levels) in children is almost entirely dependent on abdominal obesity, whereas in adolescents, the risk profile has evolved to include obesity, hyperglycemia, and dyslipidemia.³⁰ Our findings complement those in our previous study, which showed that type 2 diabetes, when it occurs during adolescence in this population, strongly predicts subsequent renal failure and death.²

Although there was no significant association between childhood hypercholesterolemia and death before 55 years of age in this young cohort, an elevated cholesterol level in childhood may emerge as a significant risk factor and other causes of death may predominate if the cohort is followed to older ages. Cholesterol levels, however, are lower in American Indians than they are in most other ethnic groups,³¹ a finding that may partially explain the absence of association for this trait. The relationship between BMI and high-density lipoprotein (HDL) cholesterol is relatively strong in Pima children (r=–0.3 to –0.6), but the relationship between BMI and total cholesterol is weaker (r=0.1).¹⁹ The effect of BMI on premature death might be attributable in part to low HDL-cholesterol concentrations, which were not measured in most of the study participants. Nevertheless, we speculate that low HDL-cholesterol levels are likely to mediate rather than confound this relationship.

It is possible that the relationship between childhood BMI and mortality is confounded by unmeasured lifestyle factors. Nevertheless, obesity can be both the cause and the consequence of adverse lifestyle factors such as physical inactivity, excessive caloric intake, and specific nutrient preferences. Thus, such factors may be important components of the causal pathway between obesity and death. It is also possible that genetic factors have pleiotropic effects on BMI and mortality.

Childhood obesity is predictive of excess mortality in several divergent settings,^20,21,22 indicating that obesity itself is causally related to either death or other commonly related factors. Even if preventing childhood obesity does not affect the risk of death, increased physical activity and modification of diet are likely to have long-term benefits. The lack of specific data on such factors is a limitation of this study.

In summary, obesity in children who do not have diabetes is associated with an increased rate of death from endogenous causes during early adulthood, an association that may be partially mediated by the development of glucose intolerance and hypertension in childhood. In contrast, the cholesterol level in childhood is not a major determinant of premature death in this population. Childhood obesity is becoming increasingly prevalent around the globe. Our observations, combined with those of other investigators, suggest that failure to reverse this trend may have wide-reaching consequences for the quality of life and longevity. Such evidence underscores the importance of preventing obesity starting in the early years of life.

Supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) intramural research program. Dr. Franks was supported in part by grants from the Swedish Diabetes Association, the Swedish Heart Lung Foundation, the Swedish Research Council, Umeå University (Career Development Award), and the Västerbotten regional health authority (Strategic Appointment 2006-09).

No potential conflict of interest relevant to this article was reported.

We thank members of the Gila River Indian Community for participating in this study and for the profound commitment this community has made over the past half century to studies that seek to further our understanding of human health and disease; the staff of the Diabetes Epidemiology and Clinical Research Section of the NIDDK for conducting the examinations; and Joy C. Bunt, M.D., Ph.D., for comments on the manuscript.

Source Information

From the Diabetes Epidemiology and Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ (P.W.F., R.L.H., W.C.K., M.L.S., P.H.B., H.C.L.); the Genetic Epidemiology and Clinical Research Group, Department of Public Health and Clinical Medicine, Section for Medicine, Umeå University Hospital, Umeå, Sweden (P.W.F.); the Medical Research Council Epidemiology Unit, Institute of Metabolic Sciences, University of Cambridge, Cambridge, United Kingdom (P.W.F.); and Mount Sinai School of Medicine, New York (H.C.L.).

Address reprint requests to Dr. Franks at the Genetic Epidemiology and Clinical Research Group, Department of Public Health and Clinical Medicine, Section for Medicine, Umeå University Hospital, Umeå 901 87, Sweden, or at paul.franks@medicin.umu.se

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10대 비만, 식이요법·운동보다 수술이 효과적”

출처 : 뉴시스 | 이진례 | 입력 2010.02.10 15:20

【시카고=로이터/뉴시스】이진례 기자 = 식욕을 억제하기 위해 위밴드수술을 받은 10대 과체중자들이 식이요법과 운동을 병행하는 10대 과체중자들보다 더욱 건강한 생활을 한다는 연구 결과가 나와 주목되고 있다.

호주 멜버른 모나시 대학의 폴 오브라이언 박사와 그의 동료들은 9일(현지시각) 미국의사협회저널에 실은 보고서에서 “연구 결과, 비만인 경우 위밴드수술을 받는 것이 체중 감량에 더욱 크고 지속적인 효과를 나타내는 것으로 나타났다”며 이와 같이 주장했다.

이들이 14세 이상~18세 이하 청소년 50명을 대상으로 실시한 결과, 위밴드수술을 받은 과체중 청소년 25명 가운데 21명은 자신의 초과 체중의 절반 이상을 뺐으나 식이요법과 운동, 행동수정프로그램을 실시한 또 다른 25명 가운데서는 단 3명만이 초과 체중의 절반 이상을 감소하는 데 성공했다.

또한 위밴드수술을 받은 지 2년이 지난 청소년들의 경우 총 신체 체중의 28.3%가 감소한 것으로 나타났는데, 이는 초과 체중의 78.8%에 해당하는 수준이다.

그러나 식이요법과 운동을 병행한 청소년의 경우 총 신체 체중의 3%만이 감소한 것으로 나타났는데, 이는 초과 체중의 13.2%에 해당하는 것이다.

아울러 위밴드수술은 비만과 더불어 신진대사증후군과 고혈압, 콜레스테롤 및 혈당 조절에 도움을 주는 것으로 나타났다.

이 연구팀이 연구를 시작할 당시 위밴드수술을 받은 청소년들 가운데 36%, 식이요법과 운동을 병행한 청소년의 40%가 신진대사증후군을 겪고 있었는데, 2년 후 위밴드수술을 받은 청소년 가운데서 신진대사증후군을 앓는 이는 한 명도 없었다. 그러나 위밴드수술을 받지 않은 청소년 가운데 22%는 여전히 신진대사증후군을 앓고 있었다.

텍사스 사우스웨스턴 의료대학의 교수이자 미국의사협회저널의 편집자인 에드워드 리빙스톤 박사는 논평을 통해 “이번 연구결과는 젊은이들을 위한 비만을 치료하는데 비만 치료 수술을 이용하는 것과 관련한 구체적인 증거를 제공해 준다”고 밝혔다.

이어 그는 “비만을 치료하기 위해 수술을 받는 것에 대한 논쟁으로, 비만 치료 수술을 지지하는 증거의 질이 조악한 상태”라며 “미국의 많은 보험사들이 비만 치료 수술을 위해서는 보험금을 지급하지 않을 것이고, 이러한 결정은 이들 지지자들의 설득력이 부족하고 일반적으로 받아들여질 수 있는 증거에 기인한 것이다”고 밝혔다.

현재 미국 어린이의 약 3분의 1이 비만을 겪고 있는 가운데, 버락 오바마 미국 대통령은 현 세대에서 해결해야할 최우선 과제 가운데 하나로 어린이 비만을 꼽고 있다.

그 동안 성인 비만과 관련된 비만 수술에 대한 안정성 및 효과에 대한 연구는 많았으나, 어린이와 10대 비만을 위한 체중감량 수술의 안전성 및 효과에 대한 연구는 부족했다.

eeka232@newsis.com

[메디컬 피트니스] 신체 활동과 운동

출처 : 프레시안 기사입력 2010-02-04 오전 9:24:16

미국스포츠의학회(American College of Sports Medicine·www.acsm.org)의 조사에 따르면, 의사들 중 40퍼센트만이 신체 활동의 필요성을 환자들에게 이야기합니다. 의사들이 환자들에게 적절한 운동이 질병 예방과 치료에 중요하다는 사실을 수시로 주지시키지는 않는 것입니다.

그 결과 병원을 찾은 환자들 중 불과 25퍼센트만이 의사로부터 운동에 대한 권고를 받는 걸로 나타났습니다. 같은 조사에서 운동이 필요한 환자들에게 객관적인 충분한 정보들이 다양한 수준에서 제공된다면, 약 65퍼센트의 환자들이 보다 큰 관심을 갖고 삶의 질 향상을 위해 운동을 실천에 옮길 수 있을 것으로 전망하고 있습니다.

이처럼 신체 활동의 증가와 운동 요법이 질병의 예방과 치료에 표준화된 일부로 정착하는 일은 매우 필요한 일입니다. 한국에서도 의학적 패러다임을 전환시키는 중요한 이슈가 될 것이라 전망됩니다.

높은 사망률을 보이는 낮은 심폐적성

심폐적성이란 개인의 운동 능력을 나타내는 주요 지표로 신체 활동이나 운동에 따른 산소소모율로 평가됩니다. 남자 40만842명과 여자 1만2943명을 대상으로 한 대규모 역학조사에서 낮은 심폐적성이 높은 사망률을 설명하는 가장 주요한 인자임이 최근 보고에 의해 밝혀졌습니다(아래 그림 참조).

여러 건강 관련 위험인자들이나 만성질병보다도 신체 활동 저하로 인한 낮은 심폐적성이 사망률에 미치는 영향이 매우 커서 21세기에 가장 큰 개인의 건강 관련 문제일 것이라는 연구결과는 우리에게도 시사하는 바가 매우 크다 할 것입니다.

ⓒ프레시안

올바른 강도의 적절한 신체 활동의 유익성

비록 낮은 수준의 운동이라 하더라도 셀 수 없을 만큼 많은 장점을 가지고 있습니다. 올바른 강도의 적절한 신체 활동은 다음과 같은 구체적이고 객관적인 유익한 점들이 있습니다.

① 심장 질환을 40퍼센트 낮춥니다.
② 뇌졸중의 위험도를 27퍼센트 줄입니다.
③ 당뇨 발생을 거의 50퍼센트 줄입니다.
④ 고혈압의 발생을 50퍼센트까지 감소시킵니다.
⑤ 유방암의 사망률과 재발 위험을 50퍼센트 줄여줄 수 있습니다.
⑥ 대장암 발생을 60퍼센트 이상 감소시킬 수 있습니다.
⑦ 알츠하이머병(알츠하이머성 치매) 발병을 3분의 1로 줄여줄 수 있습니다.
⑧ 항우울제 복용이나 행동 치료만큼이나 우울증을 감소시킬 수 있습니다.

자신의 평소 신체 활동량 알기

아래 설문은 세계보건기구(World Health Organization·www.who.int)에서 마련한 신체 활동에 대한 단축형 설문입니다. 이 설문은 지난 7일간 독자께서 신체 활동에 얼마나 많은 시간을 소모했는지를 알아보는 것입니다.

스스로 활동적이지 않다고 생각되시더라도 각 질문에 응답해 보시기 바랍니다. 직장과 집에서 하는 활동, 교통수단을 이용할 때 하는 활동, 여가 시간에 시행하는 활동, 운동 또는 스포츠 모두를 포함하여 생각해 주시기 바랍니다.

귀하가 지난 7일간 하신 모든 격렬한 활동을 생각해보십시오. 격렬한 신체 활동이란 힘들게 움직이는 활동으로서 평소보다 숨이 훨씬 더 차게 만드는 활동입니다. 한 번에 적어도 10분 이상 지속한 활동만을 생각하여 응답해주시기 바랍니다. 1. 지난 7일간 무거운 물건 나르기, 달리기, 에어로빅, 빠른 속도로 자전거타기 등과 같은 격렬한 신체 활동을 며칠간 하였습니까? 일주일에 ( ) 일 ◇ 격렬한 신체 활동 없었음 ➣ 3번으로 가세요. 2. 그런 날 중 하루에 격렬한 신체 활동을 하면서 보낸 시간이 보통 얼마나 됩니까? 하루에 ( )시간 ( )분 ◇ 모르겠다. / 확실하지 않다. 지난 7일간 중간 정도의 신체 활동(평소보다 숨이 조금 더 차게 만드는 활동)을 한 번에 적어도 10분 이상 지속한 활동만을 생각하여 응답하여 주시기 바랍니다. 3. 지난 7일간 가벼운 물건 나르기, 보통 속도로 자전거 타기, 복식 테니스 등과 같은 중간 정도의 신체 활동을 며칠간 하였습니까? (걷기는 포함시키지 마세요) 일주일에 ( )일 ◇ 중간 정도의 신체 활동이 없었음. ➣ 5번으로 가세요. 4. 그런 날 중 하루에 중간 정도의 신체 활동을 하면서 보낸 시간이 보통 얼마나 됩니까? 하루에 ( )시간 ( )분 ◇ 모르겠다. / 확실하지 않다. 지난 7일간 걸은 시간을 생각해 보세요. 직장이나 집에서 혹은 오락 활동, 스포츠, 운동, 여가시간에 걸은 것도 포함됩니다. 5. 지난 7일간 한 번에 적어도 10분 이상 걸은 날은 며칠입니까? 일주일에 ( )일 ◇ 걷지 않았음. ➣ 7번으로 가세요. 6.그런 날 중 하루에 걸으면서 보낸 시간은 보통 어마나 됩니까? 하루에 ( )시간 ( )분 ◇ 모르겠다. / 확실하지 않다. 지난 7일간 앉아서 보낸 시간에 관한 것입니다. 책상에 앉아 있거나 친구를 만나거나, 독서를 할 때 앉거나, TV를 앉아서 또는 누워서 시청한 시간이 포함됩니다. 7. 지난 7일간 주중에 앉아서 보낸 시간이 보통 얼마나 됩니까? 하루에 ( )시간 ( )분 ◇ 모르겠다. / 확실하지 않다.

개인별 신체 활동량 판정

개인별 신체 활동량을 판정하기 위해서는 신체 활동에 따른 METs(metabolic equivalents)의 총합을 구해야 합니다. METs란 운동 강도를 표현하는 단위로 안정시 산소이용률(3.5ml/kg/min)을 1METs로 할 때 상대적인 크기로 나타낸 값입니다. METs의 값을 계산하여 아래와 같이 신체 활동을 평가할 수 있습니다.

격렬한 활동(A) : 분당 8.0METs
중등도의 신체활동(B) : 분당 4.0METs
걷는 것으로 대표되는 가벼운 신체 활동(C) : 분당 3.3METs

이와 같이 얻은 활동 정도를 이용하여 신체 활동 수준을 아래와 같이 판정합니다.

1) 높은 수준의 신체 활동 : 다음 둘 중의 하나에 해당될 때.
- 격렬한 신체 활동(A)을 최소한 일주일에 3일 이상 1500MET-minutes를 한 경우
- 어떤 수준의 운동의 조합이건 매일 운동을 하여 주 3000MET-minutes 이상 한 경우

2) 중간 수준의 신체 활동 : 다음 셋 중 하나에 해당될 때.
- 격렬한 신체 활동(A)을 최소한 일주일에 3일 이상 하루에 20분 이상 한 경우
- 중간 정도의 신체 활동(B)을 최소한 일주일에 5일 이상 하루에 30분 이상 한 경우
- 어떤 수준의 운동의 조합이건 5일 이상 운동을 하여 주 600MET-minutes 이상 한 경우

3) 낮은 수준의 신체 활동 : 위의 높은 수준이나 중간 수준에 해당되지 않는 신체 활동임.

신체 활동의 수준이 낮다는 것은 심폐적성이 낮음을 의미하며, 심폐적성이 낮다는 것은 위의 그림에서 볼 수 있는 바와 같이 비만, 흡연, 고혈압, 고지혈증, 당뇨 등 익히 알려져 있는 질병이나 질병 위험인자보다 더 높은 사망률을 보여 주는 중요한 인자입니다.

그러므로 독자 여러분들께서는 적어도 중간 수준의 신체 활동을 유지할 수 있을 만큼 운동을 생활화하셔서 심폐적성이 낮은 수준에 머물지 않도록 하시는 것이 건강유지의 지름길입니다.

/공인덕 연세대학교 운동의학센터 교수,예병일 연세대학교 운동의학센터 교수