- 3.1 Introduction
- 3.2 Definition and Concept of Lifestyle
- 3.3 Lifestyle and Pre-Natal Growth
- 3.4 Lifestyle and Post-Natal Growth
3.1 INTRODUCTION
In this unit we will discuss the lifestyle-related factors that influence the physical growth. It has been observed through empirical studies that lifestyles make profound influence on attainment of size and shape in the specific periods of human physical growth, of course in this process the interaction between genetic factors and lifestyle related factors has a significant impact. What do we understand by lifestyle? It is a term that suggests how people live and what do they do on a daily basis. It is important to realize that a variety of economic, social, political and environmental factors impress upon making a particular lifestyle of an individual or a social group.
| Migration, urbanization and modernization are important demographic and ‘Social processes that bring in change in people’s lifestyle, thereby influencing the biological profile of an individual or a group through many other lifestyle related factors that includes dietary habits, physical activity pattern, psycho-social stress level, substance (alcohol, tobacco, drugs) use and the like. |
Physical growth is an intricate biological process that is reliant on genetic and environmental factors on one hand and interaction between these two sets of factors, on the other. In this unit, we will go through the studies which demonstrate the possible effects of significant lifestyle-related factors on pre- and post-natal growth profiles in human groups.
3.2 DEFINITION AND CONCEPT OF LIFESTYLE
It is very important to have an understanding on the definition and concept of lifestyle before we learn the impact of lifestyle-related factors on growth through examples contributed by the researchers.
Lifestyle according to Oxford Concise Dictionary is meant as “individual’s way of life”. Generally, lifestyle is conceived as a way of life or style of daily living r.tat echoes a particular set of attitudes, values, habits and possessions associated with a person or a group. Every individual has their own characteristic lifestyle that includes their typically chosen actions on a daily basis. Lifestyle is multifaceted as there are many things that are included in the way of life of people, thus it is a multidimensional variable comprising behavioral, socio-cultural and economic dimensions. As far as health is concerned, the most pertinent lifestyle-related factors are dietary patterns, physical activity level, psycho-social stress level, mental or emotional well-being, substance use and the like. It can thus be concluded that the habits and practices relevant to dietary and activity pattern that promote health will be part of healthy lifestyle choice. Likewise, absence of psycho-social stress, relatively higher emotional well-being and lack of substance abuse can also be part of healthy lifestyle. Yet, healthy lifestyle tends to be unhealthy lifestyle if habits and practices concerning the factors mentioned above change to such a state in which health is no more promoted.
It is a common saying that rural and urban lifestyles are not just the same; this is true because there is distinct difference between rural and urban environment attributed to many aspects of life. This is true for all the components of life- physical, biological and social. As a result of which, urban inhabitants would be adopting the urban lifestyle and rural inhabitants would be adopting rural lifestyles thus experiencing their environmental features.
Due to urbanization and modernization in the developing countries, changes have been witnessed from traditional to modern way of life, paving way for alterations that are affecting all lifestyle dimensions. You must have noticed that when there is movement from rural to urban setup, there are subsequent changes in the dietary and activity pattern. Consequently, it affects the biological profiles of individuals and populations in terms of health status and growth pattern.
Keeping in view the above, let us focus on the relationship between lifestyle-related factors and features, growth pattern, both pre- and post-natal.
3.3 LIFESTYLE AND PRE-NATAL GROWTH
When we discuss the effect of lifestyle on pre-natal growth, we are actually taking account of the lifestyle of the pregnant women; this will enable to understand the lifestyle-related factors that influence the nature and extent of fetal growth. It is clear that environment of the woman’s womb in which the fetus grows has to be favorable for survival and normal growth.
The impact of specific lifestyle-related factors on pre-natal growth is examined on the basis of some research work.
A recent study in the Netherlands, indicated that maternal lifestyle habits influence early fetal growth, measured in terms of crown-to-rump length. It came into notice that mothers who smoked and did not consume appropriate folic acid supplements during first-trimester of pregnancy had fetus with shorter crown-torump length compared with those who did not smoke and had optimal use of folic acid supplements. It also stated that the first-trimester fetal growth retardation is associated with increased risk of adverse birth outcomes, measured in terms of low birth weight, i. e. birth weight less than 2500 g, and also acceleration of growth in the early childhood (Mook-Kanamori et al., 2010).
It is construed from above that maternal lifestyle plays a decisive role in determining the nature and extent of pre-natal growth profile. It is also realized that resultant of pre-natal growth or fetal growth is assessed by fetal length and weight at birth-a vital indicator of fetal growth; although weight is given more importance since fetal prognosis is reliant on increase in fetal weight. It is undisputable that birth is the phenomenon by which the fetus makes an end of the intra-uterine life and makes emergence to a variable external environment, thus emphasizing birth weight as the most important indicator of the physical status of the new born. Nonetheless, there are many and varied factors including both genetic and environmental ones that are associated with intra-uterine growth.,
It is understood that most of the factors responsible for influencing intra-uterine outcome as depicted by birth weight are linked to maternal lifestyles, exemplified by maternal nutrition status, maternal substance use status, etc.
It is observed that birth weight is positively related to the survival potential of the newborn. Malina et al. (2004) found that full-term infants with low birth weight have 2.5 times higher relative risk of mortality compared with their norinal birth weight counterparts. The low-birth weight babies can be of two types: (a) infants who are “pre-term”. They are small in size because they are born at an early gestational age, i. e. less than 37 completed weeks. The gestational age normally is completed by 38 to 42 weeks. These infants are born with physiological immaturity; (b) infants having low birth weight are “small-for-date” or “small-for-gestational-age”. These infants have birth weights that are smaller than what is expected for their gestational age. This phenomenon is generally known as intrauterine growth retardation or fetal growth restriction (Malina et aI., 2004).
A variety of factors are held responsible for intrauterine growth retardation. For the developing countries, including India tobacco use (be it smoking and lor tobacco chewing) and maternal malnutrition portrayed by low energy intake, together with insufficient consumption of micronutrients, and cons.quent low weight gain are the most important ones. There exists rural-urban ditference in maternal undernutrition giving rise to differential prevalence of small-for-date infants. This is because among ,a vast majority of the rural women in the developing countries owing often to low socioeconomic background coupled with particular socio-cultural practices, experience low energy intake or low weight gain in addition to low prepregnant weight with a history of childhood and adolescence under-nutrition. These circumstances are favorable for the women with such characteristics to give birth to “small-for-date infants.
There are some significant lifestyle-related factors affecting pre-natal growth, especially intrauterine growth retardation are dealt separately,
It is of utmost importance that the nutrition in prenatal period is coupled with placental, fetal and maternal factors with each set of factors holding significance. The placental factors facilitates in circulation and the transportation of nutrients from the placenta to the fetus, the fetal factors assist in utilization of the available nutrients. The overall nutritional status of the mother i.e. maternal factors particularly her adequate energy and other nutrient intake during the pregnancy period, influences the nutritional state of the fetus which in turn imposes on its growth profile. The effects of maternal nutrition on fetal growth depends on the nature of energy and nutrition inadequacy if occurs, how severe it is, and how long it persists was the observation by Malina et al. (2004).
Pregnant women. found to be indulging in tobacco specifically smoking experienced intrauterine growth retardation, occurring even in the event of absence of alteration of gestational age. Babies born to women who smoke often are seen to have fetal growth restriction. It is found that in the United States, between 20% and 30% of infants having low birth weight can be attributed to the maternal smoking. It is, furthermore, observed that degree of maternal smoking is related to severity of prenatal growth restriction, which is again independent of maternal nutrition intake (Malina et aI., 2004). Shorter body length, reduced arm circumference and head
circumference are found in the newborn of mothers who smoked, thus reflectin g that maternal smoking affects body length of child at birth.
There are studies indicating consumption of alcohol,to affect the fetus in several ways including restriction of fetal growth to a considerable extent. It may influence to have facial abnormalities in the fetus, and also impaired function of the central nervous system. It is estimated that fully developed fetal alcohol syndrome, characterized by abnormal facial development, dysfunction of the central nervous system as well as stunted physical growth, will occur among around 30% of the children born to alcoholic mothers (Abel, 1982; Streissguth et al., 1980). It is also observed that higher the alcohol consumption by pregnant mothers, greater the prenatal growth restriction. Roche (1999) recorded that while consumption of 2 or less drinks a day by pregnant mothers led to a deficit of on an average 65 g in birth weight of their children, the same for the pregnant mothers consuming more than 2 drinks were found to be 150 g.
Another contributing factor to intrauterine growth restriction or growth abnormalities is the abuse of many chemical substances such as caffeine, cocaine, heroin, methadone and the like. It is established that consumption of more than 4 cups of coffee (which contains caffeine) a day during pregnancy will lead to a deficit of 220 gram in birth weight. Likewise, substance abuse in the form of cocaine, heroin, and methadone can lead to estimated deficit of 500g, 600g and 350g respectively in birth weight and 2.0 cm, 2.4 cm and 1.5 cm, respectively in birth length (Roche, 1999).
Moderate physical activity including non-strenuous physical exercise is considered essential for pregnant women for the benefit of fetal health and growth especially during first 6 to 7 months. Nevertheless, some evidence exists on association between strenuous exercise and reduced birth weight in humans (Pivarnik, 1998).
3.4 LIFESTYLE AND POST-NATAL GROWTH
Birth results in fetus getting exposed to the external environment; and immediately after birth the baby begins to adjust and adapt to the newly introduced external environment by continuously interacting with it. Human being passes through number of stages to become an adult. It takes more or less 19 to 20 years on an average to reach adulthood for a human being and in all these years, he or she is exposed to a complex biological process, namely, physical growth and maturation. It is well established that human growth process is a product of intricate interaction among the biological endowment of human species; the physical environment in which the human individuals make their living and the socio-economic and political environment that each human group creates as a cultural being.
The impact of selected lifestyle-related factors on post-natal growth profiles in human groups, as assessed through empirical evidences is reflected in the following text.
Migration of people from one place to other has been witnessed from time immemorial. Demographic, economic and political reasons force people to migrate from one place to the other for perceived or real life choices. This naturally leads to change in physical, biological and social environment and consequently will lead to changes in many facets of life leading to changes in growth pattern. In the present-day developing world, urbanization holds important aspects of development and this process is getting momentum every passing year. This has resulted in huge number of people continuously migrating to urban areas from the rural ones with a subsequent change in their lifestyle, which in turn is influencing their health and growth profiles.
Boas (1912) argued that changes in growth profile of urban migrants are due to contribution of their biological plasticity in the midst of new urban environment.
Subsequently, several studies were undertaken to demonstrate urban-rural difference in growth profiles in terms of height and other anthropometric variables. Studies conducted by Shapiro (1939) among Japanese’ children in Japan and in Hawaii; by Goldstein (1943) and Lasker (1952) among the Mexicans in Mexico and in the US are considered historical. They reflected the effect of migration on growth confirming contribution of developmental plasticity and its interaction with the changed environmental settings. Shapiro’s study demonstrated that improvements in dietary regimen, health care opportunities, and overall socio-economic status were result of migration and that these factors are associated with urban lifestyle and contributes to growth changes.
The rural-urban growth difference pattern are seen to vary; with urban advantage in growth not mandatory. During 1870-1920, the review studies revealed that rural children in the US and Europe were taller than their urban counterparts (Malina et al., 1981; Wolanski, 1990), by the 1930s the pattern reversed showing urban children to be constantly taller and heavier than the rural children. This could be attributed to the quality of the urban environments improving in the form of water and sanitation facilities, access to healthy foods, better health care services and so on in addition to improved educational and employment opportunities, that help provide health and growth benefits to urban children. But then urban poor children dwelling in slums or squatters may not have equal access to such opportunities and lag behind the urban well-off children or even rural children in growth profiles. Malina et al. (1981) revealed that children living in the slums of Oaxaca City of Mexico were significantly shorter and lighter compared with nearby rural children. Such a trend is apparent in many other developing nations, including India.
Indian studies on growth and maturation depict a trend of urban advantage in growth profiles in height and weight, and age at menarche in current scenario, but then exceptions are witnessed among the slum dwelling children. This clearly implies that soci economic resources are the prime mover that establishes advantage or disadvantage in the expression of growth pattern as modulated through lifestyle choices possible in the urban and rural settings.
Human physical growth and development are also influenced by diet and nutrition. Dietary practices constituting an important part (If lifestyle are determined by socio-economic and cultural factors. We all know thit diet serves as the sources for different nutrients essential for a growing human beeing. About 50 essential nutrients represented by carbohydrate, fat, protein, minerals, vitamins and water are generally needed for growth, maintenance and repair of the body, These nutrients are present in the food that come from plants, animals, fungi (e.g, mushrooms), protists or algae (e.g. seaweed), and eubacteria (e.g. bacteria used in fermented foods) consumed by us. Although extensive range of food items are available to us all over the world, our acceptance or rejection of type of food items depends on socioeconomic as well as sociocultural factors embedded in the lifestyles of social groups that inhabit urban or rural settings.
The growth and development of infants, children and adolescents are dependent on balanced nutritional intake is well-documented (Bogin, 1999). Natural experiments concerning different communities leading unrelated lifestyles present an opportunity to understand such dependence. Sufficient quantity of food intake is also a major determining factor for growth as food shortages in communities lead to growth deficits in children and adolescents. However, resumption of regular food supply leads to restoration of growth (catch-up growth); but then occurrence of food shortages lead to undernutrition (absence of appropriate nutrients).
In United States, studies have demonstrated that across different ethnic groups, children from lower income families were shorter and lighter as compared to their peers belonging to higher income families. This can be attributed to fact that children of the lower income families did not have the opportunity to consume sufficient food and thereby not being able to receive appropriate amount of calories needed, when compared to their peers of high income families. Socioeconomic status in such cases influences lifestyle that affects dietary consumption that is reflected in growth pattern. However there is a reversal trend during adolescence and adult stages of growth, when the lower socioeconomic groups are heavier and fatter compared to high socioeconomic group. A study by Gordon-Larsen et al. (1997) on secular changes in growth among the impoverished (economically disadvantaged) African- American juveniles and adolescents, aged 11-15 years, inhabiting Philadelphia revealed that youths in the study group remain significantly heavier and fatter, but not significantly taller when compared with the US reference growth standards. They, furthermore, found that cohorts of youth in 1990s are heavier and fatter than those measured in the 1960s and 1970s. These findings are indicative of the fact that lifestyle changes might have influenced excess calorie intake over decades for these youths.
The effects of diet and nutrition on growth as modulated by lifestyles in studies conducted in the developing world are many. Jenkin’s (1981) emphasized ethnic differences in growth pattern as a result of differential access to socioeconomic resources and cultural practices. Poor growth and higher prevalence of malnourishment among children in two of the four ethnic groups studied were linked with the frequency and severity of diarrhea, a relatively later age at introduction of solid foods and a larger number of children in the household. Bailey et al. (1984) found delay in growth in practically all dimensions among the rural Thai children when compared with local or international growth standards. When these rural children were compared with healthy middle-class children residing in the capital city of Bangkok, on an average were 4.7 cm shorter, 1.3 kg lighter, and 1.2 cm smaller in head circumference over first 3 years of life. This established the growth deficits shown by the Thai rural children from the ages 6 to 18 months when compared with the American national sample which could be a of faulty weaning practices linked with culturally attuned lifestyle habits. Although rural Guatemalan children had food sufficiency, yet, the traditional dietary practices of consuming corn and beans deprived them of caloric sufficiency necessary for proper growth (Behar, 1977).,Cultural practices related to infant and child feeding could lead to population variation in nutrition and growth profiles have been demonstrated. Sudden changes in such cultural practices through nutritional intervention or behavioral changes lead to consequent changes in growth patterns. The significance of specific foods on successful growth achievements is an important aspect of investigation.
Rich nutrient food will undisputably help infant, children and adolescents grow faster. It has been demonstrated beyond any doubt that breast milk is the best food for the newborns and the infants as milk has all the nutrients they-require, It becomes of prime importance the mother’s willingness or capability in exclusive breastfeeding practices. Unfortunately it has come to notice that there is decrease in the duration of breast feeding practice owing to modernization more so among the urban educated mother. Rapid culture change has resulted in substantial proportion of mothers in developed as well as developing countries to depend on bottle feeding using infant formulas or milk from other animal sources, which has serious health consequences for the infants. Breastfeeding holds immense significance as it provides emotional bonding with mother, positive health/consequences for the infant including absence of infective agents, and so on. A recommendation by World Health Organization suggests that infants should have exclusive breastfeeding from birth to 6 months of age. They should be on the breastfed in addition to nutritionally adequate supplemental foods until they reach the age of two years or older. Stinson I (2000) argued that breast-fed babies grow faster than the bottle-fed babies during the first year of life, in the developing countries. This is attributed to the fact that infants fed with formula can have relatively higher rate 6f illnesses, such as diarrhea that contributes to growth faltering. Takahashi (1984) observed that increased
Consumption of milk by infants, children and juveniles has a direct relationship with gr-eater average height of a Japanese population. Similar observations were indicated by little et a1. (1983). It is well established that milk contains essential nutrients sue h as vitamin D3and calcium that help normal bone formation and growth in height, therefore increased milk consumption becomes helpful in grow th in height in Populations. Proper consumption of micro-nutrients like iron, iodine, zinc or vitamin A is essential so as to avoid growth retardation. The changes in the lifestyle due to modernizing forces make dietary changes altering micronutrient consumption pattern in populations of the developing world, that impinge on changes in growth profile s.
Physical activity constitutes an important component of an individual’s lifestyle. Human beings of all ages are required to perform certain amount of physical activity to maintain proper health. It is agreed that a sedentary lifestyle engages very little or no 1ihysical activity, whereas balanced lifestyle involves a proper combination of all activities rest, sleep, work, physical activity, leisure and recreation in daily life.
Habitual physical activity is evolntionarily produced genetically determined need for the humans to maintain optimal metabolic function. Rationally, below normal (hyp 0-) or above normal (hyper-) activity pose risk to appropriate growth of children, Childhood and adolescence are the period when nutrition and physical activity contrrbute to the growth of several body tissues such as flit, muscle and bone. The ideal combination of both appropriate nutrition and physical activity makes an ideal and appropriate pattern of growth and maturation in children and adolescents (Hills et aI., 200- 7),
Regular physical activity from early childhood paves way for good health for coming ye ars i.e. in mid- or late adulthood, If the desired pattern of habitual activity begins at an early age and sustained through later age, influences future health status and longevity. Physical activity considered to be a normal part of growth and development, promotes both physical and emotional health of growing children. Though its different stages physical activity varies, an insufficient level of physical activity ‘in any of the stages may lead to overweight and obesity.
Parental guidance in early childhood is an important determinant of physical activity, since the attitudes and lifestyles of parents decides whether the child is regularly physically active. However, the school-going children and college-going grown up adolescents and young adults are influenced more by peers, in their extent of indulgence in physical activity. It is undisputable that in the current situation in the developed nations and also in the urban centers of the developing countries a considerable proport ‘on of children, adolescents and young adults are adapting to sedentary lifestyles by enjoying television viewing and playing computer games and so 0n. Gortrnaker et-al. (I 9~16)reported that in North America, a child or an adolescent is estimated to spend three to four hours per day on this kind of leisure activities. Due to a series of changes in the social environment, a substantial proportion of youngsters have lost the Opportunity. to be physically active in the contemporary world is rather unfortunate Sallis (2000)is of the view that gradual decline in physical activity between childhood arid adolescence is a robust epidemiological phenomenon. Social, environmental and biological factors are working in unison for such a phenomenon to occer Technological advancements, globalization with ensuing market economy, attitudinal modernization, cash flow ‘and consumerism and the like have been prime factors related to such a behaviour.
There is rampant increase in overweight and obesity among children and adolescents. The situation warrants immediate public health attention to prevent it spreading its tentacles, determined effort to motivate children and adolescents to adopt an active lifestyle is desirable. In fact we need ‘0 put relentless efforts to reduce the number of children and adolescents adapted to sedentary lifestyle, in order to combat the I here is not much work reported on effects or smoking on post- natal growth.
However, Rona et al. (1981) put forward evidence to suggest that growth deficits in height occur due to passive smoking. Furthermore, Schell et al. (1986) concluded that maternal smoking during pregnancy affected measures of adiposity among children aged 6-11years; significant reductions in these measures were found among the children whose mothers smoked during pregnancy.
It has been noticed that psychological or emotional factors in the form of psychosocial stress act negatively on child growth. There are studies to demonstrate the negative effect of psychosocial and emotional stress on growth and maturation (Money, 1977). This condition is sometimes called as “psychosocial dwarfism” or “deprivation dwarfism”. It is found that such condition can lead to stunting and delayed maturity for three years. Factors responsible for such event could be maternal deprivation, isolation of the child, disorganized or broken family life, and also physical abuse. Possibly, “deprivation dwarfism” leads to suppression or impairment of growth hormone production and impaired nutrient utilization (Malina et al., 2004). Hulanicka (1999) found shorter height and earlier age 8ft menarche for girls experiencing family distress and consequently living a life with psychosocial stress. A recent observation of concern for weight or the fear’ of’ weight gain is evidenced among the adolescent girls of the developed world, and to some extent in the developing countries. Moore (1993) found a substantial proportion of adolescent girls in the US are not satisfied with their weight. Consequent.ly, many girls are practicing self-imposed dieting. The outcome of such behavior is the appearance’ of severe malnutrition among them as well as growth failure and delayed maturation (Lifshitz and Moses, 1988) among them. Sudden changes in the social environment and breaking down of age old social institutions has paved way for rapid changes in the lifestyles, that are creating ample stressful behavior which is affecting human biology of many social groups in the contemporary world .
It is well understood that growth and development are sensitive to extensive variety of environmental features. In the current scenario, anthropogenic features of environment affect growth and development. Air pollution; pollution of heavy metals viz, mercury, lead; pesticides and herbicides, such as DDT and dioxin and radiation and noise are reflected to be the anthropogenic features of the environment. Most of the anthropogenic features are recent developments and POSl sibly they will pose adaptive challenges which will be reflected in patterns of growth I .Schell and Knutsen, 2002). There are studies to substantiate that human physical growth and development are .sensitive to several pollutants like lead, the components of air pollution, organic compounds such as polychlorinated biphenyls, as well as some forms of energy such as radiation and noise. Taking into consideration the changes taking place, modem life will bring forth many pew agents in the form of pollutants in the environment that may upset growth and development of children and adolescents.
Sample Questions
- Describe lifestyle, What are the impact of lifestyle changes of the social groups due to urbanization?
- What are the significant features of lifestyle of mothers that influence pre-natal growth?
- Dietary practices ‘are vital determinants of post-natal growth. Explain with examples.
- Explain the role of physical activity in promoting growth of children and adolescents