(2007) 410–415www.elsevier.com/locate/ypmed

Preventive Medicine 44

Adolescents' physical activity in relation to family incomeand parents' education

Marko T. Kantomaa a,b,⁎, Tuija H. Tammelin c, Simo Näyhä a,c, Anja M. Taanila a

a Department of Public Health Science and General Practice, University of Oulu, Oulu, Finlandb Young Finland Association, Radiokatu 20, 00240 Helsinki, Finland

c Finnish Institute of Occupational Health, Oulu, Finland

Available online 1 February 2007

Abstract

Objective. Regular physical activity provides young people with important physical, mental, and social health benefits. This study aimed toevaluate the relationship of family income and parents' level of education with physical activity in Finnish adolescents.

Method. The study population consisted of the Northern Finland Birth Cohort 1986, including 5457 boys and girls aged 15–16 years, and theirparents who responded to a postal inquiry in 2001–2002. The associations between social background and adolescents' physical activity wereanalyzed in 2005 using cross-tabulation and multivariate logistic regression.

Results. High parental education was associated with adolescents being physically active. In boys father's high educational level (OR: 0.56; CI:0.33, 0.95), and in girls both mother's (OR: 0.55; CI: 0.31, 0.98) and father's (OR: 0.35; CI: 0.20, 0.61) high educational levels were related to theleast time spent watching TV. High family income was associated with being an active sports club member in boys (OR: 2.43; CI: 1.74, 3.40) andgirls (OR: 2.67; CI: 1.81, 3.94). Adolescents' participation in different types of physical activity varied according to family income.

Conclusions. Economic support for youth sports and informing parents on ways to encourage adolescents' physical activity are recommendedto ensure equal opportunities for youths to participate in different physical activities.© 2007 Elsevier Inc. All rights reserved.

Keywords: Physical activity; Income; Education; Adolescent

Introduction

Regular physical activity provides adolescents with impor-tant physical, mental, and social health benefits (Department ofHealth, Physical Activity, Health Improvement and Prevention,2004). Despite the well-known advantages of physical activity,most young people are not active enough to benefit from them.According to recent studies (National Research and Develop-ment Centre for Welfare and Health (STAKES), 2004; Robertset al., 2004) approximately 25% of Finnish adolescents exercisealarmingly little.

Social status is one of the key factors in health and well-being (Acheson, 1998; Marmot et al., 1991; Kennedy et al.,

⁎ Corresponding author. Young Finland Association, Radiokatu 20, 00240Helsinki, Finland. Fax: +358 9 3481 2007.

E-mail address: marko.kantomaa@nuorisuomi.fi (M.T. Kantomaa).

0091-7435/$ - see front matter © 2007 Elsevier Inc. All rights reserved.doi:10.1016/j.ypmed.2007.01.008

1996). However, most relevant research has focused primarilyon morbidity and mortality (Marmot et al., 1991; Kennedy etal., 1996; Wilkinson, 1986) with evidence for the role of socialstatus in health behavior and health risks being less convincing.Moreover, most studies on socioeconomic status in relation tohealth have concentrated on infants, young children, and adults(Wilkinson, 1986; LeGrand, 1987; Kunst et al., 1998) and onlya few on adolescents.

A link between physical activity among adolescents and thefamily's social status is commonly believed to exist. Highfamily income (U.S. Department of Health and HumanServices, 1996; Mo et al., 2005; Lethbridge-Çejku et al.,2004) and high parental education (Lasheras et al., 2001;Gordon-Larsen et al., 2000; Oehlschlaeger et al., 2004) arethought to be related to intense physical activity and a decreasedlikelihood of being inactive. In their recent paper, Gorely et al.(2004) conclude that parents' income and education correlatenegatively and a single-parent/guardian family positively with

Table 1Sample characteristics of subjects in the Northern Finland Birth Cohort 1986 in2001–2002

Boys Girls

N (total) % N (total) %

Brisk physical activity outside school hoursNot at all 170 6.8 177 6.9

411M.T. Kantomaa et al. / Preventive Medicine 44 (2007) 410–415

the time spent watching TV. Much of the earlier research onsocial status, family income, and adolescents' physical activityhas obtained the relevant information from adolescentsthemselves, which may be fallacious since few young peopleknow their parents' income or can adequately describe theiroccupation (Currie et al., 1997).

To promote a physically active lifestyle among children andyouth, we need more information on socioeconomic factorsunderlying physical activity, inactivity, and highly prevalentsedentary behaviors. This study therefore examines how familyincome and parental education are associated with physicalactivity and TV watching among adolescents, and howparticipation in different types of physical activity is modifiedby the adolescent's social background. We hypothesize that (1)high family income and parental education are associateddirectly with physical activity and being a member in a sportsclub, and inversely with TV watching, and (2) types of physicalactivity requiring expensive equipment or participation fees aremore typical of high-income families.

About 1/2 h a week 308 12.3 400 15.6About 1 h a week 298 11.9 474 18.52–3 h a week 578 23.1 750 29.2About 4–6 h a week 572 22.9 502 19.57 h a week or more 576 23.0 266 10.4

Sports club membershipNo 1683 67.1 1887 73.3Yes, but does not attend training sessions 87 3.5 142 5.5Yes, and attends training sessions 737 29.4 544 21.2

Watching TV (h/day)<1 1/2 563 22.5 645 25.01 1/2–3 1/2 1324 52.9 1389 53.8>3 1/2 618 24.6 546 21.2

Annual family income/consumption unit (€)I ≥18,600 664 24.6 677 25.8II 13,600–18,599 693 25.7 644 24.4III 9200–13,599 657 24.4 649 24.6IV <9200 682 25.3 665 25.2

Mother's educationI Tertiary/higher 384 14.4 355 13.7II Upper secondary 1837 69.0 1804 69.3III Basic (≤9 years) 153 5.7 149 5.7IV Other or degree not finished 289 10.9 295 11.3

Father's educationI Tertiary/higher 333 13.1 293 11.8II Upper secondary 1753 68.7 1753 70.7III Basic (≤9 years) 292 11.4 258 10.4IV Other or degree not finished 173 6.8 177 7.1

Change in family typeAlways two-parent family 1929 76.1 1839 74.5Single-parent family 369 14.5 340 13.8Reconstructed family 218 8.6 264 10.7Always one-parent family 20 0.8 27 1.0

Place of residenceRural 1312 47.6 1298 48.1Semi-urban 436 15.8 403 15.0Urban 1011 36.6 996 36.9

Mother's level of physical activityActive 1206 48.3 1125 46.0Moderately active 593 23.7 621 25.4Inactive 700 28.0 701 28.6

Father's level of physical activityActive 994 42.8 918 40.8Moderately active 516 22.2 518 23.0Inactive 812 35.0 816 36.2

Methods

Study setting and population

The study population comprised the Northern Finland Birth Cohort 1986,which originally contained 9432 children who were born alive and whoseexpected date of birth was between 1 July, 1985 and 30 June 1986 in the twonorthernmost provinces of Finland (Oulu and Lapland) (Järvelin et al., 1993).The data collection started during the pregnancy of their mothers and has sincebeen repeated at age 7–8 years (1993–1994) and 15–16 years (2001–2002)(hereafter referred to as “16 years”). At this survey, 7344 adolescents filled in apostal questionnaire (80% of those who received it) asking about types andlevels of physical activity and sedentary behavior. Their parents (6985, 76% ofall) were also sent a questionnaire that included questions on family income,mother's and father's education, family structure, and place of residence. Thepresent analyses include only those 5457 subjects whose family income andphysical activity were reported. Informed consent was obtained from allparticipants, and the research protocol was approved by the Ethics Committee ofthe University Hospital of Oulu.

Measurement of physical activity and sedentary activities

At the age of 16 years, the subjects were asked about their participation inbrisk physical activity outside school hours, time spent viewing TV, membershipin a sport club and participation in different types of sports. The amount of briskphysical activitywas evaluated by asking “Howmuch do you participate in briskphysical activity outside school hours?” In the questionnaire, the term ‘brisk’was defined as physical activity causing at least some sweating and getting outof breath. The response alternatives were not at all, about 1/2 h a week, about 1 ha week, 2–3 h a week, 4–6 h a week, 7 h or more in a week. Those whoparticipated in brisk physical activity 4 h or more per week were classified as“physically active”. Test–retest reliability of this question has been good(intraclass correlation coefficient of 0.78) among Finnish adolescents aged15 years old (Vuori et al., 2005). Time spent on watching TV was classified as 1)less than 1 1/2 h, 2) more than 1 1/2 h but less than 3 1/2 h, and 3) 3 1/2 h or moreper day. The subjects were categorized as “active sport club members” if theywere members in a sport club and participated in training sessions. The subjectsalso reported how often they participated in different types of physical activityduring the previous year in the season which was suitable for those activities.Those who participated in a certain sport once a week or more often wereclassified as active participants in that particular sport. These sports wereselected into the questionnaire as they were reported being most popular sportsamong Finnish young people in 1997–1998 (Nurmela and Pehkonen, 1998).

Family income and parents' education

Information describing the socioeconomic status of the family was obtainedfrom parents. Annual income was enquired about in the questionnaire, and toenable comparison of households of different sizes and structures, householdconsumption units (OECD scale) were calculated by assigning the first adult inthe household a value of 1.0, with additional adults (>17 years) receiving 0.7and each child (≤17 years) 0.5 (OECD, 1982; United Nations, 1977). Thefamilies were classified into quartiles based on their annual income perconsumption unit: 1) less than 9200€, 2) 9200–13,599€, 3) 13,600–18,599€,and 4) more than 18,600 € per year. Mother's and father's highest level ofeducationwas also categorized according to educational level categories used bythe International Standard Classification of Education (ISCED) (Classification

412 M.T. Kantomaa et al. / Preventive Medicine 44 (2007) 410–415

in Education, 1998) and the Finnish National Board of Education (2006). Theoriginal educational levels were 1) less than 9 years of primary education, 2)basic education, 3) matriculation examination, 4) vocational course, 5)vocational education, 6) vocational college, 7) polytechnic, 8) university, and9) other or degree not finished. These nine educational groups were merged toform the four larger categories of 1) basic education, lasting ≤9 years (originallevels 1–2); 2) upper secondary education, lasting 10–12 years (original levels3–6); 3) tertiary education, lasting ≥13 years (original levels 7–8); and 4) otheror degree not finished (original level 9).

Potential confounding factors

Factors considered potential confounders were family type, place ofresidence, and parents' level of physical activity. Information on family typewas obtained from (1) questionnaires filled out by mothers during pregnancyand (2) postal questionnaires sent to parents when the child was aged 7 and16 years. Family type was divided into four different categories: 1) always two-parent family; the child lived with his/her biological parents who were marriedor cohabiting, 2) single-parent family; the child lived with his/her biologicalparent who were divorced, separated, or widowed, 3) reconstructed family; thechild lived in a family where his/her biological parent had divorced, separated,or been widowed but now had a new spouse or partner, or the mother had beensingle at the time of the child's birth but married or cohabited later, 4) alwaysone-parent family; the child lived in a family where the mother had nevermarried or cohabited. Place of residence was also obtained from the parents'questionnaire and coded according to the Finnish Regional Researchclassification of municipalities in 2000 into urban, semi-urban, and ruralmunicipalities (Keränen et al., 2000). Parents' level of physical activity wasbased on a question asking about the frequency of participation in brisk physicalactivity during leisure-time. Parents were classified into three groups: 1) active:exercising briskly twice a week or more often; 2) moderately active: exercisingbriskly once a week; and 3) inactive: exercising briskly less than once a week.

Statistical analyses

Cross-tabulation and multivariate logistic regression were used to evaluatehow family income and parents' level of education were associated with beingactive, watching TV, and being an active sports club member. Odds ratios (OR)and their 95% confidence intervals (CI) were calculated for the explanatoryfactors and adjusted for family type, place of residence, and parents' level of

Table 2Physically active a adolescents by background characteristics

Boys (N=2494)

Active subjects(%)

UnadjustedOR (CI)

Annual family income/consumption unit (€)I ≥18,600 52.7 1.55 (1.19, 2.02)II 13,600–18,599 45.9 1.24 (0.95, 1.63)III 9200–13,599 46.0 1.38 (1.05, 1.81)IV <9200 40.1 1.00

Mother's educationI Tertiary/higher 55.4 2.37 (1.44, 3.92)II Upper secondary 45.3 1.65 (1.05, 2.60)III Basic (≤9 years) 37.8 1.00IV Other or degree not finished 46.0 1.84 (1.09, 3.10)

Father's educationI Tertiary/higher 57.1 2.20 (1.49, 3.26)II Upper secondary 45.9 1.52 (1.10, 2.09)III Basic (≤9 years) 37.9 1.00IV Other or degree not finished 45.2 1.55 (0.98, 2.44)

Multivariate regression of physical activity at age 16 years in the Northern Finlanda Exercised briskly for more than 4 h a week.b Adjusted for all variables in the table as well as for change in family type, plac

confidence interval.

education. Statistical analyses were carried out using SPSS software, version12.0 (SPSS Inc., Chicago, Illinois, USA, 2003).

Results

Sample characteristics

Boys participated in brisk physical activities more frequentlythan girls and were more often active members of sports clubsthan girls (Table 1). The highest income group had an annualfamily income of more than 18,600 €, compared with less than9200 € in the lowest income group. About 14% of adolescentshad a mother and 12% a father with tertiary/higher education;the corresponding figures for children of parents with basiceducation were 6% and 11% (Table 1).

Physical activity

In logistic regressions, high family income was initiallyassociated with physical activity in boys (OR: 1.55; CI: 1.19,2.02) and girls (OR: 1.57; CI: 1.18, 2.08) but did not remainsignificant once allowance was made for parents' level ofeducation. Both mother's high educational level (in boys OR:1.82; CI: 1.06, 3.12) (in girls OR: 1.98; CI: 1.08, 3.66) andfather's high educational level (in boys OR: 1.58; CI: 1.02,2.43) (in girls OR: 1.70; CI: 1.07, 2.70) were independentlyassociated with being physically active (Table 2).

Sports club activity

In both genders, family income was positively associatedwith being an active sports club member (Table 3). This asso-ciation remained in both, boys (OR: 2.43; CI: 1.74, 3.40) andgirls (OR: 2.67; CI: 1.81, 3.94), after adjustments were made in

Girls (N=2565)

Adjusted b

OR (CI)Active subjects(%)

UnadjustedOR (CI)

Adjusted b

OR (CI)

1.17 (0.88, 1.57) 32.9 1.57 (1.18, 2.08) 1.25 (0.92, 1.70)1.08 (0.82, 1.43) 33.5 1.49 (1.12, 1.98) 1.29 (0.95, 1.74)1.27 (0.96, 1.68) 26.7 0.98 (0.72, 1.33) 0.92 (0.67, 1.26)1.00 26.9 1.00 1.00

1.82 (1.06, 3.12) 38.3 2.85 (1.59, 5.12) 1.98 (1.08, 3.66)1.43 (0.90, 2.29) 29.4 1.93 (1.12, 3.31) 1.68 (0.97, 2.93)1.00 22.6 1.00 1.001.62 (0.95, 2.78) 27.8 1.58 (0.86, 2.93) 1.38 (0.74, 2.60)

1.58 (1.02, 2.43) 41.9 2.31 (1.50, 3.56) 1.70 (1.07, 2.70)1.32 (0.95, 1.84) 29.5 1.26 (0.88, 1.81) 1.10 (0.76, 1.59)1.00 26.5 1.00 1.001.25 (0.78, 1.99) 26.1 1.06 (0.64, 1.76) 0.95 (0.56, 1.61)

Birth Cohort 1986 in 2001–2002.

e of residence, and parents' level of physical activity. OR, odds ratio; CI, 95%

Table 3Active sports club members a by background characteristics

Boys (N=2507) Girls (N=2573)

Active sportsclub members(%)

UnadjustedOR (CI)

Adjusted b

OR (CI)Active sportsclub members(%)

UnadjustedOR (CI)

Adjusted b

OR (CI)

Annual family income/consumption unit (€)I ≥18,600 38.4 2.99 (2.19, 4.08) 2.43 (1.74, 3.40) 31.2 3.83 (2.66, 5.52) 2.67 (1.81, 3.94)II 13,600–18,599 33.4 2.50 (1.83, 3.43) 2.32 (1.67, 3.21) 25.2 3.10 (2.14, 4.50) 2.38 (1.62, 3.49)III 9200–13,599 27.9 2.02 (1.45, 2.80) 1.94 (1.39, 2.71) 17.3 1.72 (1.15, 2.58) 1.57 (1.04, 2.37)IV <9200 18.2 1.00 1.00 10.7 1.00 1.00

Mother's educationI Tertiary/higher 37.3 2.62 (1.44, 4.74) 1.38 (0.73, 2.62) 28.8 3.58 (1.71, 7.50) 1.81 (0.83, 3.94)II Upper secondary 29.1 1.95 (1.12, 3.41) 1.48 (0.83, 2.63) 21.4 2.56 (1.27, 5.16) 1.80 (0.87, 3.72)III Basic (≤9 years) 20.4 1.00 1.00 10.9 1.00 1.00IV Other or degree not finished 28.2 1.95 (1.05, 3.64) 1.51 (0.79, 2.89) 16.7 1.84 (0.84, 4.04) 1.30 (0.58, 2.91)

Father's educationI Tertiary/higher 41.9 2.87 (1.86, 4.43) 2.05 (1.27, 3.31) 30.6 3.43 (2.02, 5.81) 1.91 (1.09, 3.36)II Upper secondary 29.0 1.61 (1.11, 2.35) 1.35 (0.92, 1.99) 20.8 1.85 (1.16, 2.96) 1.47 (0.91, 2.39)III Basic (≤9 years) 20.7 1.00 1.00 13.8 1.00 1.00IV Other or degree not finished 28.9 1.61 (0.96, 2.69) 1.26 (0.74, 2.15) 22.8 2.36 (1.30, 4.26) 1.88 (1.02, 3.49)

Multivariate regression of membership at age 16 years in the Northern Finland Birth Cohort 1986 in 2001–2002.a Were members in a sports club and participated in training sessions.b Adjusted for all variables in the table as well as for change in family type, place of residence, and parents' level of physical activity. OR, odds ratio; CI, 95%

confidence interval.

413M.T. Kantomaa et al. / Preventive Medicine 44 (2007) 410–415

the model for parents' education and other variables. In thecrude analyses, both mother's and father's education were posi-tively associated with adolescents' sports club memberships, butonly father's education remained significant in boys (OR: 2.05;CI: 1.27, 3.31) and girls (OR: 1.91; CI: 1.09, 3.36) onceallowance was made for mother's education and family income.

Television watching

Parents' educational level was inversely associated with timespent watching TV for adolescents. For example, 31% of girls

Table 4Adolescents watching television for more than 3 1/2 h a day by background charac

Boys (N=2505)

TV time ≥3 1/2 h/day (%)

UnadjustedOR (CI)

Annual family income/consumption unit (€)I ≥18,600 21.9 0.82 (0.60, 1.12)II 13,600–18,599 26.7 1.18 (0.87, 1.59)III 9200–13,599 24.8 0.93 (0.68, 1.27)IV <9200 25.7 1.00

Mother's educationI Tertiary/higher 16.1 0.63 (0.35, 1.14)II Upper secondary 25.6 1.16 (0.70, 1.93)III Basic (≤9 years) 24.1 1.00IV Other or degree not finished 29.1 1.42 (0.79, 2.52)

Father's educationI Tertiary/higher 14.1 0.47 (0.28, 0.76)II Upper secondary 26.3 1.04 (0.74, 1.48)III Basic (≤9 years) 25.9 1.00IV Other or degree not finished 19.6 0.70 (0.41, 1.21)

Multivariate regression of television watching at age 16 years in the Northern Finlaa Adjusted for all variables in the table as well as for change in family type, plac

confidence interval.

whose father had only a basic education but 11% of girls with ahighly educated father watched TV for 3 1/2 h a day or more;comparable proportions were seen in boys (Table 4). Regardingmother's education, the findings were similar in girls (OR: 0.55;CI: 0.31, 0.98), in boys the association was not significant (OR:0.79; CI: 0.42, 1.49).

Types of physical activity

Participation in different types of physical activity variedbetween family income groups, although most associations

teristics

Girls (N=2580)

Adjusted a

OR (CI)TV time ≥3 1/2 h/day (%)

UnadjustedOR (CI)

Adjusted a

OR (CI)

1.03 (0.73, 1.45) 18.7 0.91 (0.66, 1.26) 1.18 (0.83, 1.68)1.26 (0.92, 1.72) 21.5 1.08 (0.79, 1.49) 1.24 (0.89, 1.74)0.95 (0.69, 1.31) 20.7 0.89 (0.63, 1.24) 0.94 (0.67, 1.33)1.00 22.7 1.00 1.00

0.79 (0.42, 1.49) 13.9 0.44 (0.26, 0.77) 0.55 (0.31, 0.98)1.20 (0.71, 2.03) 21.2 0.58 (0.37, 0.92) 0.63 (0.39, 1.01)1.00 34.1 1.00 1.001.48 (0.82, 2.68) 22.6 0.66 (0.38, 1.14) 0.76 (0.43, 1.34)

0.56 (0.33, 0.95) 10.8 0.33 (0.19, 0.57) 0.35 (0.20, 0.61)1.08 (0.76, 1.55) 20.9 0.73 (0.51, 1.04) 0.76 (0.52, 1.10)1.00 30.6 1.00 1.000.72 (0.41, 1.25) 15.0 0.44 (0.25, 0.79) 0.43 (0.23, 0.78)

nd Birth Cohort 1986 in 2001–2002.e of residence, and parents' level of physical activity. OR, odds ratio; CI, 95%

414 M.T. Kantomaa et al. / Preventive Medicine 44 (2007) 410–415

were weak. Participation in downhill skiing increased withincreasing family income in both sexes (p<0.01), but theassociations were variable regarding most other types ofactivity. Among boys, participation in tennis and golf, andamong girls, participation in aerobics and dancing was morecommon in the highest income group (p<0.01). However,swimming, ice hockey, bandy, volleyball, and athletics weremore common in the lowest income group in both genders(p<0.01), and in girls, also cross-country skiing and soccer(p<0.01).

Discussion

A positive association between physical activity amongadolescents and mother's and father's educational level haspreviously been reported (Lasheras et al., 2001; Gordon-Larsenet al., 2000; McVeigh et al., 2004). However, some studies(Lasheras et al., 2001) have used only the educational level ofthe head of the household, and others (McVeigh et al., 2004)have examined children, but not adolescents. Some investiga-tors suggest that adolescents from high-income families arephysically more active than their peers from low-incomefamilies (U.S. Department of Health and Human Services,1996; Lasheras et al., 2001; Gordon-Larsen et al., 2000), but inour analysis this association disappeared once parents' educa-tion was taken into account. Thus, parental education seems tobe a more powerful factor in adolescents' physical activity thanfamily income as such. Here, parents' level of education wasinversely associated with the time spent watching TV, consistentwith the result in one previous study (Gorely et al., 2004), whileanother study found no association between TV watching andsocial class (Lindquist et al., 1999).

High family income seemed to be a stronger determinant ofsports club membership than parents' level of education,although this remained significant only in boys with respectto father's education after adjustments. Our finding is in linewith that of Sallis et al. (1996), who reported that highsocioeconomic status and frequent participation in organizedsports after school hours are correlated; socioeconomic statushad, however, been determined differently, based on schooldistrict.

The few studies published on the association betweenfamily's socioeconomic status and participation in differentphysical activities among youths have yielded inconsistentresults. Here, the likelihood of participating in the physicalactivities of downhill skiing, roller skating, badminton, andtennis among boys, and aerobics, gymnastics, and dancingamong girls increased rather consistently with increasing familyincome, while the trend was the opposite for most othersports. This is more or less in line with a previous report fromFinland stating that downhill skiing and dancing, for example,are typical of adolescents who come from the highest socialclass, whereas strength sports are more characteristic of thelower social classes (Tammelin et al., 2003). Sallis et al.(1996), by contrast, contended that socioeconomic status wasnot a major factor in the selection of after-school activities byadolescents.

Our finding of an association between family's socio-economic status and participation in certain types of sports ispartly contrary to our hypothesis but could be interpreted interms of the theory of diffusion of innovations (Ferrence, 1996),which postulates that new lifestyles spread through populationsin waves, first being adopted by higher social classes andsubsequently by others. The higher prevalence of most types ofsports in the lower income groups and other sports in the higherincome groups may merely indicate differences in timing ofbehaviors.

The study setting does not allow us to make strongconclusions about direct causality between socioeconomicstatus of the family and physical activity in youth. There maybe some other factors related to socioeconomic status of thefamily which are linked to physical activity of the children. Ininterpreting the results of our study and extrapolating them toother populations, it is important to recognize that differencesbetween social classes are relatively small in Finland (OECD,2005); the median income in 2001 was 16,821 €, the povertylimit being 10,092 € (Statistics Finland, 2006). It is also worthtaking cognizance of that the Finnish government alreadysupports child and youth sport financially through sportsorganizations and national federations, and physical activity insports clubs differs substantially from physical education inschools. Finally, socioeconomic status may not be an optimalmodifiable target for physical activity promotion strategies, butrather may be an important means by which we can identifygroups of individuals that are in need.

Study limitations and strengths

Strengths of our study include large general population anddata on income and social status directly from the parents. Onthe other hand, reliance on self-reported physical activity is alimitation in surveys of this kind. Social desirability bias maylead to overestimating the time or intensity of physical activity,and for children and youths, errors in recall are likely to begreater than for adults (Montoye et al., 1996; Shephard, 2003).Some of the factors characterizing social status, especiallyfamily income and parental education, were interrelated; highereducation tended to be linked to higher income. To evaluate thestrongest social determinants of physical activity, we first testedthe crude associations between individual social factors andphysical activity, making adjustments thereafter.

Conclusions

Our findings confirm earlier results of an associationbetween social determinants and physical activity in youths;high family income and parent's high level of education werepositively associated with the levels and types of physicalactivity in adolescents. Today, child and youth sport may causeconsiderable costs to families. To enable equal opportunities toparticipate in physical activities, economic support to youthsport is necessary. Also parents should be systematicallyinformed on the importance of physical activity in maintaininghealth.

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Acknowledgment

This study was partly funded by the Ministry of Education,Finland.

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