Table 2.
Socioeconomic inequalities in FMI, FFMI, and FM:FFM at age 7 years, and changes in inequalities across childhood and adolescence
|
Difference in body composition at age 7 by SEP |
SEP × age (in years) interaction |
Age × sex interaction value | SEP × sex interaction p value | ||||
|---|---|---|---|---|---|---|---|
| Coefficient (95% CI) | p value | Coefficient (95% CI) | p value | ||||
| Index of Multiple Deprivation | |||||||
| FMI | |||||||
| 1: Age | −0·042 (−0·058 to −0·026) | <0·0001 | −0·012 (−0·015 to −0·008) | <0·0001 | NA | NA | |
| 2: Model 1 + sex | −0·038 (−0·054 to −0·022) | <0·0001 | −0·012 (−0·015 to −0·008) | <0·0001 | NA | NA | |
| 3: Model 2 + age × sex | −0·028 (−0·047 to −0·010) | 0·003 | −0·012 (−0·015 to −0·008) | <0·0001 | <0·0001 | 0·053 | |
| 4: Model 3 + ethnicity | −0·025 (−0·044 to −0·007) | 0·008 | −0·012 (−0·015 to −0·008) | <0·0001 | <0·0001 | 0·05 | |
| 5: Model 4 + education + occupational social class + income | 0·003 (−0·017 to 0·023) | 0·76 | −0·012 (−0·015 to −0·008) | <0·0001 | <0·0001 | 0·053 | |
| FFMI | |||||||
| 1: Age | −0·069 (−0·098 to −0·040) | <0·0001 | 0·002 (−0·003 to 0·006) | 0·5 | NA | NA | |
| 2: Model 1 + sex | −0·059 (−0·88 to −0·029) | <0·0001 | 0·000 (−0·004 to 0·005) | 0·83 | NA | NA | |
| 3: Model 2 + age × sex | −0·062 (−0·093 to −0·030) | <0·0001 | 0·003 (−0·001 to 0·007) | 0·20 | <0·0001 | 0·23 | |
| 4: Model 3 + ethnicity | −0·061 (−0·093 to −0·029) | 0·0002 | 0·002 (−0·002 to 0·007) | 0·25 | <0·0001 | 0·24 | |
| 5: Model 4 + education + occupational social class + income | −0·044 (−0·077 to −0·010) | 0·001 | 0·002 (−0·002 to 0·007) | 0·25 | <0·0001 | 0·25 | |
| 6: Model 4 + FMI | −0·041 (−0·069 to −0·013) | 0·004 | 0·012 (0·008 to 0·016) | <0·0001 | <0·0001 | 0·12 | |
| 7: Model 5 + FMI | −0·055 (−0·084 to −0·026) | 0·0002 | 0·012 (0·008 to 0·016) | <0·0001 | <0·0001 | 0·11 | |
| FM:FFM | |||||||
| 1: Age | −0·004 (−0·006 to −0·002) | 0·0001 | −0·001 (−0·001 to −0·001) | <0·0001 | NA | NA | |
| 2: Model 1 + sex | −0·003 (−0·005 to −0·002) | 0·0002 | −0·001 (−0·001 to −0·001) | <0·0001 | NA | NA | |
| 3: Model 2 + age × sex | −0·003 (−0·006 to −0·001) | 0·002 | −0·001 (−0·001 to −0·001) | <0·0001 | <0·0001 | 0·62 | |
| 4: Model 3 + ethnicity | −0·003 (−0·005 to −0·001) | 0·011 | −0·001 (−0·001 to −0·001) | <0·0001 | <0·0001 | 0·60 | |
| 5: Model 4 + education + occupational social class + income | 0·000 (−0·003 to 0·002) | 0·78 | −0·001 (−0·001 to 0·000) | <0·0001 | <0·0001 | 0·61 | |
| Income quintile | |||||||
| FMI | |||||||
| 1: Age | −0·041 (−0·054 to −0·027) | <0·0001 | −0·012 (−0·015 to −0·008) | <0·0001 | NA | NA | |
| 2: Model 1 + sex | −0·040 (−0·053 to −0·027) | <0·0001 | −0·012 (−0·015 to −0·008) | <0·0001 | NA | NA | |
| 3: Model 2 + age × sex | −0·033 (−0·050 to −0·016) | 0·0002 | −0·012 (−0·015 to −0·008) | <0·0001 | <0·0001 | 0·17 | |
| 4: Model 3 + ethnicity | −0·030 (−0·047 to −0·013) | 0·001 | −0·012 (−0·015 to −0·008) | <0·0001 | <0·0001 | 0·17 | |
| FFMI | |||||||
| 1: Age | −0·077 (−0·100 to −0·051) | <0·0001 | 0·008 (0·003 to 0·013) | 0·001 | NA | NA | |
| 2: Model 1 + sex | −0·071 (−0·097 to −0·044) | <0·0001 | 0·006 (0·002 to 0·011) | 0·006 | NA | NA | |
| 3: Model 2 + age × sex | −0·069 (−0·099 to −0·039) | <0·0001 | 0·007 (0·002 to 0·011) | 0·003 | <0·0001 | 0·64 | |
| 4: Model 3 + ethnicity | −0·072 (−0·100 to −0·042) | <0·0001 | 0·006 (0·002 to 0·011) | 0·004 | <0·0001 | 0·67 | |
| 6: Model 4 + FMI | −0·055 (−0·082 to −0·029) | <0·0001 | 0·017 (0·013 to 0·020) | <0·0001 | <0·0001 | 0·67 | |
| FM:FFM | |||||||
| 1: Age | −0·004 (−0·005 to −0·002) | <0·0001 | −0·001 (−0·001 to −0·001) | <0·0001 | NA | NA | |
| 2: Model 1 + sex | −0·004 (−0·005 to −0·002) | <0·0001 | −0·001 (−0·001 to −0·001) | <0·0001 | NA | NA | |
| 3: Model 2 + age × sex | −0·003 (−0·005 to −0·001) | 0·004 | −0·001 (−0·001 to −0·001) | <0·0001 | <0·0001 | 0·29 | |
| 4: Model 3 + ethnicity | −0·002 (−0·004 to 0·000) | 0·022 | −0·001 (−0·001 to −0·001) | <0·0001 | <0·0001 | 0·28 | |
Index of Multiple Deprivation groups are ranked from 1 (lowest) to 5 (highest). Income quintiles are ranked from the lowest to the highest fifth on income. Coefficients for difference in body composition at age 7 years show the change in body composition for one unit increase in SEP. The coefficients for SEP × age interaction show the change in body composition per one unit increase in SEP per 1 year increase in age. Results presented are for models that include the SEP × sex interaction, except models 1 and 2. FMI=fat mass index. FFMI=fat free mass index. FM:FFM=fat mass to fat free mass ratio. SEP=socioeconomic position. NA=not applicable.